mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

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targets/TARGET_Maxim/TARGET_MAX32620C/mxc/owm.c@189:f392fc9709a3, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 22:31:08 2019 +0000
Revision:
189:f392fc9709a3
Parent:
186:707f6e361f3e 
mbed library release version 165

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Anna Bridge 186:707f6e361f3e 1 /**
Anna Bridge 186:707f6e361f3e 2 * @file
Anna Bridge 186:707f6e361f3e 3 * @brief 1-Wire Master (OWM) API Function Implementations.
Anna Bridge 186:707f6e361f3e 4 */
Anna Bridge 186:707f6e361f3e 5 /* *****************************************************************************
Anna Bridge 186:707f6e361f3e 6 * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
Anna Bridge 186:707f6e361f3e 7 *
Anna Bridge 186:707f6e361f3e 8 * Permission is hereby granted, free of charge, to any person obtaining a
Anna Bridge 186:707f6e361f3e 9 * copy of this software and associated documentation files (the "Software"),
Anna Bridge 186:707f6e361f3e 10 * to deal in the Software without restriction, including without limitation
Anna Bridge 186:707f6e361f3e 11 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
Anna Bridge 186:707f6e361f3e 12 * and/or sell copies of the Software, and to permit persons to whom the
Anna Bridge 186:707f6e361f3e 13 * Software is furnished to do so, subject to the following conditions:
Anna Bridge 186:707f6e361f3e 14 *
Anna Bridge 186:707f6e361f3e 15 * The above copyright notice and this permission notice shall be included
Anna Bridge 186:707f6e361f3e 16 * in all copies or substantial portions of the Software.
Anna Bridge 186:707f6e361f3e 17 *
Anna Bridge 186:707f6e361f3e 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
Anna Bridge 186:707f6e361f3e 19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
Anna Bridge 186:707f6e361f3e 20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
Anna Bridge 186:707f6e361f3e 21 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
Anna Bridge 186:707f6e361f3e 22 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
Anna Bridge 186:707f6e361f3e 23 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
Anna Bridge 186:707f6e361f3e 24 * OTHER DEALINGS IN THE SOFTWARE.
Anna Bridge 186:707f6e361f3e 25 *
Anna Bridge 186:707f6e361f3e 26 * Except as contained in this notice, the name of Maxim Integrated
Anna Bridge 186:707f6e361f3e 27 * Products, Inc. shall not be used except as stated in the Maxim Integrated
Anna Bridge 186:707f6e361f3e 28 * Products, Inc. Branding Policy.
Anna Bridge 186:707f6e361f3e 29 *
Anna Bridge 186:707f6e361f3e 30 * The mere transfer of this software does not imply any licenses
Anna Bridge 186:707f6e361f3e 31 * of trade secrets, proprietary technology, copyrights, patents,
Anna Bridge 186:707f6e361f3e 32 * trademarks, maskwork rights, or any other form of intellectual
Anna Bridge 186:707f6e361f3e 33 * property whatsoever. Maxim Integrated Products, Inc. retains all
Anna Bridge 186:707f6e361f3e 34 * ownership rights.
Anna Bridge 186:707f6e361f3e 35 *
Anna Bridge 186:707f6e361f3e 36 * $Date: 2016-03-14 10:08:53 -0500 (Mon, 14 Mar 2016) $
Anna Bridge 186:707f6e361f3e 37 * $Revision: 21855 $
Anna Bridge 186:707f6e361f3e 38 *
Anna Bridge 186:707f6e361f3e 39 **************************************************************************** */
Anna Bridge 186:707f6e361f3e 40
Anna Bridge 186:707f6e361f3e 41 /* **** Includes **** */
Anna Bridge 186:707f6e361f3e 42 #include <string.h>
Anna Bridge 186:707f6e361f3e 43 #include "mxc_assert.h"
Anna Bridge 186:707f6e361f3e 44 #include "mxc_sys.h"
Anna Bridge 186:707f6e361f3e 45 #include "owm.h"
Anna Bridge 186:707f6e361f3e 46
Anna Bridge 186:707f6e361f3e 47 /**
Anna Bridge 186:707f6e361f3e 48 * @ingroup owm
Anna Bridge 186:707f6e361f3e 49 * @{
Anna Bridge 186:707f6e361f3e 50 */
Anna Bridge 186:707f6e361f3e 51 ///@cond
Anna Bridge 186:707f6e361f3e 52 /* **** Definitions **** */
Anna Bridge 186:707f6e361f3e 53 #define OWM_CLK_FREQ 1000000 //1-Wire requires 1MHz clock
Anna Bridge 186:707f6e361f3e 54
Anna Bridge 186:707f6e361f3e 55 /* **** Globals **** */
Anna Bridge 186:707f6e361f3e 56 int LastDiscrepancy;
Anna Bridge 186:707f6e361f3e 57 int LastDeviceFlag;
Anna Bridge 186:707f6e361f3e 58
Anna Bridge 186:707f6e361f3e 59 /* **** Functions **** */
Anna Bridge 186:707f6e361f3e 60 static uint8_t CalculateCRC8(uint8_t* data, int len);
Anna Bridge 186:707f6e361f3e 61 static uint8_t update_crc8(uint8_t crc, uint8_t value);
Anna Bridge 186:707f6e361f3e 62 ///@endcond
Anna Bridge 186:707f6e361f3e 63
Anna Bridge 186:707f6e361f3e 64
Anna Bridge 186:707f6e361f3e 65 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 66 int OWM_Init(mxc_owm_regs_t *owm, const owm_cfg_t *cfg, const sys_cfg_owm_t *sys_cfg)
Anna Bridge 186:707f6e361f3e 67 {
Anna Bridge 186:707f6e361f3e 68 int err = 0;
Anna Bridge 186:707f6e361f3e 69 uint32_t owm_clk, clk_div = 0;
Anna Bridge 186:707f6e361f3e 70 uint32_t ext_pu_mode = 0;
Anna Bridge 186:707f6e361f3e 71 uint32_t ext_pu_polarity = 0;
Anna Bridge 186:707f6e361f3e 72
Anna Bridge 186:707f6e361f3e 73 // Check the OWM register pointer is valid
Anna Bridge 186:707f6e361f3e 74 MXC_ASSERT(MXC_OWM_GET_IDX(owm) >= 0);
Anna Bridge 186:707f6e361f3e 75
Anna Bridge 186:707f6e361f3e 76 if(cfg == NULL) {
Anna Bridge 186:707f6e361f3e 77 return E_NULL_PTR;
Anna Bridge 186:707f6e361f3e 78 }
Anna Bridge 186:707f6e361f3e 79
Anna Bridge 186:707f6e361f3e 80 // Set system level configurations
Anna Bridge 186:707f6e361f3e 81 if ((err = SYS_OWM_Init(owm, sys_cfg)) != E_NO_ERROR) {
Anna Bridge 186:707f6e361f3e 82 return err;
Anna Bridge 186:707f6e361f3e 83 }
Anna Bridge 186:707f6e361f3e 84
Anna Bridge 186:707f6e361f3e 85 // Configure clk divisor to get 1MHz OWM clk
Anna Bridge 186:707f6e361f3e 86 owm_clk = SYS_OWM_GetFreq(owm);
Anna Bridge 186:707f6e361f3e 87
Anna Bridge 186:707f6e361f3e 88 if(owm_clk == 0) {
Anna Bridge 186:707f6e361f3e 89 return E_UNINITIALIZED;
Anna Bridge 186:707f6e361f3e 90 }
Anna Bridge 186:707f6e361f3e 91
Anna Bridge 186:707f6e361f3e 92 // Return error if clk doesn't divide evenly to 1MHz
Anna Bridge 186:707f6e361f3e 93 if(owm_clk % OWM_CLK_FREQ) {
Anna Bridge 186:707f6e361f3e 94 return E_NOT_SUPPORTED;
Anna Bridge 186:707f6e361f3e 95 }
Anna Bridge 186:707f6e361f3e 96
Anna Bridge 186:707f6e361f3e 97 clk_div = (owm_clk / (OWM_CLK_FREQ));
Anna Bridge 186:707f6e361f3e 98
Anna Bridge 186:707f6e361f3e 99 // Can not support lower frequencies
Anna Bridge 186:707f6e361f3e 100 if(clk_div == 0) {
Anna Bridge 186:707f6e361f3e 101 return E_NOT_SUPPORTED;
Anna Bridge 186:707f6e361f3e 102 }
Anna Bridge 186:707f6e361f3e 103
Anna Bridge 186:707f6e361f3e 104 // Select the PU mode and polarity based on cfg input
Anna Bridge 186:707f6e361f3e 105 switch(cfg->ext_pu_mode)
Anna Bridge 186:707f6e361f3e 106 {
Anna Bridge 186:707f6e361f3e 107 case OWM_EXT_PU_ACT_HIGH:
Anna Bridge 186:707f6e361f3e 108 ext_pu_mode = MXC_V_OWM_CFG_EXT_PULLUP_MODE_USED;
Anna Bridge 186:707f6e361f3e 109 ext_pu_polarity = MXC_V_OWM_CTRL_STAT_EXT_PULLUP_POL_ACT_HIGH;
Anna Bridge 186:707f6e361f3e 110 break;
Anna Bridge 186:707f6e361f3e 111 case OWM_EXT_PU_ACT_LOW:
Anna Bridge 186:707f6e361f3e 112 ext_pu_mode = MXC_V_OWM_CFG_EXT_PULLUP_MODE_USED;
Anna Bridge 186:707f6e361f3e 113 ext_pu_polarity = MXC_V_OWM_CTRL_STAT_EXT_PULLUP_POL_ACT_LOW;
Anna Bridge 186:707f6e361f3e 114 break;
Anna Bridge 186:707f6e361f3e 115 case OWM_EXT_PU_UNUSED:
Anna Bridge 186:707f6e361f3e 116 ext_pu_mode = MXC_V_OWM_CFG_EXT_PULLUP_MODE_UNUSED;
Anna Bridge 186:707f6e361f3e 117 ext_pu_polarity = MXC_V_OWM_CTRL_STAT_EXT_PULLUP_POL_ACT_HIGH;
Anna Bridge 186:707f6e361f3e 118 break;
Anna Bridge 186:707f6e361f3e 119 default:
Anna Bridge 186:707f6e361f3e 120 return E_BAD_PARAM;
Anna Bridge 186:707f6e361f3e 121 }
Anna Bridge 186:707f6e361f3e 122
Anna Bridge 186:707f6e361f3e 123 // Set clk divisor
Anna Bridge 186:707f6e361f3e 124 owm->clk_div_1us = (clk_div << MXC_F_OWM_CLK_DIV_1US_DIVISOR_POS) & MXC_F_OWM_CLK_DIV_1US_DIVISOR;
Anna Bridge 186:707f6e361f3e 125
Anna Bridge 186:707f6e361f3e 126 // Set configuration
Anna Bridge 186:707f6e361f3e 127 owm->cfg = (((cfg->int_pu_en << MXC_F_OWM_CFG_INT_PULLUP_ENABLE_POS) & MXC_F_OWM_CFG_INT_PULLUP_ENABLE) |
Anna Bridge 186:707f6e361f3e 128 ((ext_pu_mode << MXC_F_OWM_CFG_EXT_PULLUP_MODE_POS) & MXC_F_OWM_CFG_EXT_PULLUP_MODE) |
Anna Bridge 186:707f6e361f3e 129 ((cfg->long_line_mode << MXC_F_OWM_CFG_LONG_LINE_MODE) & MXC_F_OWM_CFG_LONG_LINE_MODE_POS));
Anna Bridge 186:707f6e361f3e 130
Anna Bridge 186:707f6e361f3e 131 owm->ctrl_stat = (((ext_pu_polarity << MXC_F_OWM_CTRL_STAT_EXT_PULLUP_POL_POS) & MXC_F_OWM_CTRL_STAT_EXT_PULLUP_POL) |
Anna Bridge 186:707f6e361f3e 132 ((cfg->overdrive_spec << MXC_F_OWM_CTRL_STAT_OD_SPEC_MODE_POS) & MXC_F_OWM_CTRL_STAT_OD_SPEC_MODE));
Anna Bridge 186:707f6e361f3e 133
Anna Bridge 186:707f6e361f3e 134 // Clear all interrupt flags
Anna Bridge 186:707f6e361f3e 135 owm->intfl = owm->intfl;
Anna Bridge 186:707f6e361f3e 136
Anna Bridge 186:707f6e361f3e 137 return E_NO_ERROR;
Anna Bridge 186:707f6e361f3e 138 }
Anna Bridge 186:707f6e361f3e 139
Anna Bridge 186:707f6e361f3e 140 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 141 int OWM_Shutdown(mxc_owm_regs_t *owm)
Anna Bridge 186:707f6e361f3e 142 {
Anna Bridge 186:707f6e361f3e 143 int err;
Anna Bridge 186:707f6e361f3e 144
Anna Bridge 186:707f6e361f3e 145 // Disable and clear interrupts
Anna Bridge 186:707f6e361f3e 146 owm->inten = 0;
Anna Bridge 186:707f6e361f3e 147 owm->intfl = owm->intfl;
Anna Bridge 186:707f6e361f3e 148
Anna Bridge 186:707f6e361f3e 149 // Release IO pins and disable clk
Anna Bridge 186:707f6e361f3e 150 if ((err = SYS_OWM_Shutdown(owm)) != E_NO_ERROR) {
Anna Bridge 186:707f6e361f3e 151 return err;
Anna Bridge 186:707f6e361f3e 152 }
Anna Bridge 186:707f6e361f3e 153
Anna Bridge 186:707f6e361f3e 154 return E_NO_ERROR;
Anna Bridge 186:707f6e361f3e 155 }
Anna Bridge 186:707f6e361f3e 156
Anna Bridge 186:707f6e361f3e 157 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 158 int OWM_Reset(mxc_owm_regs_t *owm)
Anna Bridge 186:707f6e361f3e 159 {
Anna Bridge 186:707f6e361f3e 160 owm->intfl = MXC_F_OWM_INTFL_OW_RESET_DONE; // Clear the reset flag
Anna Bridge 186:707f6e361f3e 161 owm->ctrl_stat |= MXC_F_OWM_CTRL_STAT_START_OW_RESET; // Generate a reset pulse
Anna Bridge 186:707f6e361f3e 162 while((owm->intfl & MXC_F_OWM_INTFL_OW_RESET_DONE) == 0); // Wait for reset time slot to complete
Anna Bridge 186:707f6e361f3e 163
Anna Bridge 186:707f6e361f3e 164 return (!!(owm->ctrl_stat & MXC_F_OWM_CTRL_STAT_PRESENCE_DETECT)); // Return presence pulse detect status
Anna Bridge 186:707f6e361f3e 165 }
Anna Bridge 186:707f6e361f3e 166
Anna Bridge 186:707f6e361f3e 167 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 168 int OWM_TouchByte(mxc_owm_regs_t *owm, uint8_t data)
Anna Bridge 186:707f6e361f3e 169 {
Anna Bridge 186:707f6e361f3e 170 owm->cfg &= ~MXC_F_OWM_CFG_SINGLE_BIT_MODE; // Set to 8 bit mode
Anna Bridge 186:707f6e361f3e 171 owm->intfl = (MXC_F_OWM_INTFL_TX_DATA_EMPTY | MXC_F_OWM_INTFL_RX_DATA_READY); // Clear the flags
Anna Bridge 186:707f6e361f3e 172 owm->data = (data << MXC_F_OWM_DATA_TX_RX_POS) & MXC_F_OWM_DATA_TX_RX; // Write data
Anna Bridge 186:707f6e361f3e 173 while((owm->intfl & MXC_F_OWM_INTFL_TX_DATA_EMPTY) == 0); // Wait for data to be sent
Anna Bridge 186:707f6e361f3e 174 while((owm->intfl & MXC_F_OWM_INTFL_RX_DATA_READY) == 0); // Wait for data to be read
Anna Bridge 186:707f6e361f3e 175
Anna Bridge 186:707f6e361f3e 176 return (owm->data >> MXC_F_OWM_DATA_TX_RX_POS) & 0xFF; // Return the data read
Anna Bridge 186:707f6e361f3e 177 }
Anna Bridge 186:707f6e361f3e 178
Anna Bridge 186:707f6e361f3e 179 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 180 int OWM_WriteByte(mxc_owm_regs_t *owm, uint8_t data)
Anna Bridge 186:707f6e361f3e 181 {
Anna Bridge 186:707f6e361f3e 182 // Send one byte of data and verify the data sent = data parameter
Anna Bridge 186:707f6e361f3e 183 return (OWM_TouchByte(owm, data) == data) ? E_NO_ERROR : E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 184 }
Anna Bridge 186:707f6e361f3e 185
Anna Bridge 186:707f6e361f3e 186 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 187 int OWM_ReadByte(mxc_owm_regs_t *owm)
Anna Bridge 186:707f6e361f3e 188 {
Anna Bridge 186:707f6e361f3e 189 // Read one byte of data
Anna Bridge 186:707f6e361f3e 190 return OWM_TouchByte(owm, 0xFF);
Anna Bridge 186:707f6e361f3e 191 }
Anna Bridge 186:707f6e361f3e 192
Anna Bridge 186:707f6e361f3e 193 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 194 int OWM_TouchBit(mxc_owm_regs_t *owm, uint8_t bit)
Anna Bridge 186:707f6e361f3e 195 {
Anna Bridge 186:707f6e361f3e 196 MXC_OWM->cfg |= MXC_F_OWM_CFG_SINGLE_BIT_MODE; // Set to 1 bit mode
Anna Bridge 186:707f6e361f3e 197 owm->intfl = (MXC_F_OWM_INTFL_TX_DATA_EMPTY | MXC_F_OWM_INTFL_RX_DATA_READY); // Clear the flags
Anna Bridge 186:707f6e361f3e 198 owm->data = (bit << MXC_F_OWM_DATA_TX_RX_POS) & MXC_F_OWM_DATA_TX_RX; // Write data
Anna Bridge 186:707f6e361f3e 199 while((owm->intfl & MXC_F_OWM_INTFL_TX_DATA_EMPTY) == 0); // Wait for data to be sent
Anna Bridge 186:707f6e361f3e 200 while((owm->intfl & MXC_F_OWM_INTFL_RX_DATA_READY) == 0); // Wait for data to be read
Anna Bridge 186:707f6e361f3e 201
Anna Bridge 186:707f6e361f3e 202 return (owm->data >> MXC_F_OWM_DATA_TX_RX_POS) & 0x1; // Return the bit read
Anna Bridge 186:707f6e361f3e 203 }
Anna Bridge 186:707f6e361f3e 204
Anna Bridge 186:707f6e361f3e 205 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 206 int OWM_WriteBit(mxc_owm_regs_t *owm, uint8_t bit)
Anna Bridge 186:707f6e361f3e 207 {
Anna Bridge 186:707f6e361f3e 208 // Send a bit and verify the bit sent = bit parameter
Anna Bridge 186:707f6e361f3e 209 return (OWM_TouchBit(owm, bit) == bit) ? E_NO_ERROR : E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 210 }
Anna Bridge 186:707f6e361f3e 211
Anna Bridge 186:707f6e361f3e 212 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 213 int OWM_ReadBit(mxc_owm_regs_t *owm)
Anna Bridge 186:707f6e361f3e 214 {
Anna Bridge 186:707f6e361f3e 215 // Read a bit
Anna Bridge 186:707f6e361f3e 216 return OWM_TouchBit(owm, 1);
Anna Bridge 186:707f6e361f3e 217 }
Anna Bridge 186:707f6e361f3e 218
Anna Bridge 186:707f6e361f3e 219 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 220 int OWM_Write(mxc_owm_regs_t *owm, uint8_t* data, int len)
Anna Bridge 186:707f6e361f3e 221 {
Anna Bridge 186:707f6e361f3e 222 int num = 0;
Anna Bridge 186:707f6e361f3e 223
Anna Bridge 186:707f6e361f3e 224 owm->cfg &= ~MXC_F_OWM_CFG_SINGLE_BIT_MODE; // Set to 8 bit mode
Anna Bridge 186:707f6e361f3e 225
Anna Bridge 186:707f6e361f3e 226 while(num < len) // Loop for number of bytes to write
Anna Bridge 186:707f6e361f3e 227 {
Anna Bridge 186:707f6e361f3e 228 owm->intfl = (MXC_F_OWM_INTFL_TX_DATA_EMPTY | MXC_F_OWM_INTFL_RX_DATA_READY | MXC_F_OWM_INTEN_LINE_SHORT); // Clear the flags
Anna Bridge 186:707f6e361f3e 229 owm->data = (data[num] << MXC_F_OWM_DATA_TX_RX_POS) & MXC_F_OWM_DATA_TX_RX; // Write data
Anna Bridge 186:707f6e361f3e 230 while((owm->intfl & MXC_F_OWM_INTFL_TX_DATA_EMPTY) == 0); // Wait for data to be sent
Anna Bridge 186:707f6e361f3e 231 while((owm->intfl & MXC_F_OWM_INTFL_RX_DATA_READY) == 0); // Wait for data to be read
Anna Bridge 186:707f6e361f3e 232
Anna Bridge 186:707f6e361f3e 233 // Verify data sent is correct
Anna Bridge 186:707f6e361f3e 234 if(owm->data != data[num]) {
Anna Bridge 186:707f6e361f3e 235 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 236 }
Anna Bridge 186:707f6e361f3e 237
Anna Bridge 186:707f6e361f3e 238 // Check error flag
Anna Bridge 186:707f6e361f3e 239 if(owm->intfl & MXC_F_OWM_INTEN_LINE_SHORT) {
Anna Bridge 186:707f6e361f3e 240 return E_COMM_ERR; // Wire was low before transaction
Anna Bridge 186:707f6e361f3e 241 }
Anna Bridge 186:707f6e361f3e 242
Anna Bridge 186:707f6e361f3e 243 num++; // Keep track of how many bytes written
Anna Bridge 186:707f6e361f3e 244 }
Anna Bridge 186:707f6e361f3e 245
Anna Bridge 186:707f6e361f3e 246 return num; // Return number of bytes written
Anna Bridge 186:707f6e361f3e 247 }
Anna Bridge 186:707f6e361f3e 248
Anna Bridge 186:707f6e361f3e 249 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 250 int OWM_Read(mxc_owm_regs_t *owm, uint8_t* data, int len)
Anna Bridge 186:707f6e361f3e 251 {
Anna Bridge 186:707f6e361f3e 252 int num = 0;
Anna Bridge 186:707f6e361f3e 253
Anna Bridge 186:707f6e361f3e 254 owm->cfg &= ~MXC_F_OWM_CFG_SINGLE_BIT_MODE; // Set to 8 bit mode
Anna Bridge 186:707f6e361f3e 255
Anna Bridge 186:707f6e361f3e 256 while(num < len) // Loop for number of bytes to read
Anna Bridge 186:707f6e361f3e 257 {
Anna Bridge 186:707f6e361f3e 258 owm->intfl = (MXC_F_OWM_INTFL_TX_DATA_EMPTY | MXC_F_OWM_INTFL_RX_DATA_READY | MXC_F_OWM_INTEN_LINE_SHORT); // Clear the flags
Anna Bridge 186:707f6e361f3e 259 owm->data = 0xFF; // Write 0xFF for a read
Anna Bridge 186:707f6e361f3e 260 while((owm->intfl & MXC_F_OWM_INTFL_TX_DATA_EMPTY) == 0); // Wait for data to be sent
Anna Bridge 186:707f6e361f3e 261 while((owm->intfl & MXC_F_OWM_INTFL_RX_DATA_READY) == 0); // Wait for data to be read
Anna Bridge 186:707f6e361f3e 262
Anna Bridge 186:707f6e361f3e 263 // Check error flag
Anna Bridge 186:707f6e361f3e 264 if(owm->intfl & MXC_F_OWM_INTEN_LINE_SHORT) {
Anna Bridge 186:707f6e361f3e 265 return E_COMM_ERR; // Wire was low before transaction
Anna Bridge 186:707f6e361f3e 266 }
Anna Bridge 186:707f6e361f3e 267
Anna Bridge 186:707f6e361f3e 268 // Store read data into buffer
Anna Bridge 186:707f6e361f3e 269 data[num] = (owm->data >> MXC_F_OWM_DATA_TX_RX_POS) & MXC_F_OWM_DATA_TX_RX;
Anna Bridge 186:707f6e361f3e 270
Anna Bridge 186:707f6e361f3e 271 num++; // Keep track of how many bytes read
Anna Bridge 186:707f6e361f3e 272 }
Anna Bridge 186:707f6e361f3e 273
Anna Bridge 186:707f6e361f3e 274 return num; // Return number of bytes read
Anna Bridge 186:707f6e361f3e 275 }
Anna Bridge 186:707f6e361f3e 276
Anna Bridge 186:707f6e361f3e 277 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 278 int OWM_ReadROM(mxc_owm_regs_t *owm, uint8_t* ROMCode)
Anna Bridge 186:707f6e361f3e 279 {
Anna Bridge 186:707f6e361f3e 280 int num_read = 0;
Anna Bridge 186:707f6e361f3e 281
Anna Bridge 186:707f6e361f3e 282 // Send reset and wait for presence pulse
Anna Bridge 186:707f6e361f3e 283 if(OWM_Reset(owm))
Anna Bridge 186:707f6e361f3e 284 {
Anna Bridge 186:707f6e361f3e 285 // Send Read ROM command code
Anna Bridge 186:707f6e361f3e 286 if(OWM_WriteByte(owm, READ_ROM_COMMAND) == E_NO_ERROR)
Anna Bridge 186:707f6e361f3e 287 {
Anna Bridge 186:707f6e361f3e 288 // Read 8 bytes and store in buffer
Anna Bridge 186:707f6e361f3e 289 num_read = OWM_Read(owm, ROMCode, 8);
Anna Bridge 186:707f6e361f3e 290
Anna Bridge 186:707f6e361f3e 291 // Check the number of bytes read
Anna Bridge 186:707f6e361f3e 292 if(num_read != 8) {
Anna Bridge 186:707f6e361f3e 293 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 294 }
Anna Bridge 186:707f6e361f3e 295 }
Anna Bridge 186:707f6e361f3e 296 else
Anna Bridge 186:707f6e361f3e 297 {
Anna Bridge 186:707f6e361f3e 298 // Write failed
Anna Bridge 186:707f6e361f3e 299 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 300 }
Anna Bridge 186:707f6e361f3e 301 }
Anna Bridge 186:707f6e361f3e 302 else
Anna Bridge 186:707f6e361f3e 303 {
Anna Bridge 186:707f6e361f3e 304 // No presence pulse
Anna Bridge 186:707f6e361f3e 305 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 306 }
Anna Bridge 186:707f6e361f3e 307
Anna Bridge 186:707f6e361f3e 308 return E_NO_ERROR;
Anna Bridge 186:707f6e361f3e 309 }
Anna Bridge 186:707f6e361f3e 310
Anna Bridge 186:707f6e361f3e 311 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 312 int OWM_MatchROM(mxc_owm_regs_t *owm, uint8_t* ROMCode)
Anna Bridge 186:707f6e361f3e 313 {
Anna Bridge 186:707f6e361f3e 314 int num_wrote = 0;
Anna Bridge 186:707f6e361f3e 315
Anna Bridge 186:707f6e361f3e 316 // Send reset and wait for presence pulse
Anna Bridge 186:707f6e361f3e 317 if(OWM_Reset(owm))
Anna Bridge 186:707f6e361f3e 318 {
Anna Bridge 186:707f6e361f3e 319 // Send match ROM command code
Anna Bridge 186:707f6e361f3e 320 if(OWM_WriteByte(owm, MATCH_ROM_COMMAND) == E_NO_ERROR)
Anna Bridge 186:707f6e361f3e 321 {
Anna Bridge 186:707f6e361f3e 322 // Write 8 bytes in ROMCode buffer
Anna Bridge 186:707f6e361f3e 323 num_wrote = OWM_Write(owm, ROMCode, 8);
Anna Bridge 186:707f6e361f3e 324
Anna Bridge 186:707f6e361f3e 325 // Check the number of bytes written
Anna Bridge 186:707f6e361f3e 326 if(num_wrote != 8) {
Anna Bridge 186:707f6e361f3e 327 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 328 }
Anna Bridge 186:707f6e361f3e 329 }
Anna Bridge 186:707f6e361f3e 330 else
Anna Bridge 186:707f6e361f3e 331 {
Anna Bridge 186:707f6e361f3e 332 // Write failed
Anna Bridge 186:707f6e361f3e 333 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 334 }
Anna Bridge 186:707f6e361f3e 335 }
Anna Bridge 186:707f6e361f3e 336 else
Anna Bridge 186:707f6e361f3e 337 {
Anna Bridge 186:707f6e361f3e 338 // No presence pulse
Anna Bridge 186:707f6e361f3e 339 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 340 }
Anna Bridge 186:707f6e361f3e 341
Anna Bridge 186:707f6e361f3e 342 return E_NO_ERROR;
Anna Bridge 186:707f6e361f3e 343 }
Anna Bridge 186:707f6e361f3e 344
Anna Bridge 186:707f6e361f3e 345 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 346 int OWM_ODMatchROM(mxc_owm_regs_t *owm, uint8_t* ROMCode)
Anna Bridge 186:707f6e361f3e 347 {
Anna Bridge 186:707f6e361f3e 348 int num_wrote = 0;
Anna Bridge 186:707f6e361f3e 349
Anna Bridge 186:707f6e361f3e 350 // Set to standard speed
Anna Bridge 186:707f6e361f3e 351 owm->cfg &= ~(MXC_F_OWM_CFG_OVERDRIVE);
Anna Bridge 186:707f6e361f3e 352
Anna Bridge 186:707f6e361f3e 353 // Send reset and wait for presence pulse
Anna Bridge 186:707f6e361f3e 354 if(OWM_Reset(owm))
Anna Bridge 186:707f6e361f3e 355 {
Anna Bridge 186:707f6e361f3e 356 // Send Overdrive match ROM command code
Anna Bridge 186:707f6e361f3e 357 if(OWM_WriteByte(owm, OD_MATCH_ROM_COMMAND) == E_NO_ERROR)
Anna Bridge 186:707f6e361f3e 358 {
Anna Bridge 186:707f6e361f3e 359 // Set overdrive
Anna Bridge 186:707f6e361f3e 360 owm->cfg |= MXC_F_OWM_CFG_OVERDRIVE;
Anna Bridge 186:707f6e361f3e 361
Anna Bridge 186:707f6e361f3e 362 // Write 8 bytes in ROMCode buffer
Anna Bridge 186:707f6e361f3e 363 num_wrote = OWM_Write(owm, ROMCode, 8);
Anna Bridge 186:707f6e361f3e 364
Anna Bridge 186:707f6e361f3e 365 // Check the number of bytes written
Anna Bridge 186:707f6e361f3e 366 if(num_wrote != 8) {
Anna Bridge 186:707f6e361f3e 367 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 368 }
Anna Bridge 186:707f6e361f3e 369 }
Anna Bridge 186:707f6e361f3e 370 else
Anna Bridge 186:707f6e361f3e 371 {
Anna Bridge 186:707f6e361f3e 372 // Write failed
Anna Bridge 186:707f6e361f3e 373 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 374 }
Anna Bridge 186:707f6e361f3e 375 }
Anna Bridge 186:707f6e361f3e 376 else
Anna Bridge 186:707f6e361f3e 377 {
Anna Bridge 186:707f6e361f3e 378 // No presence pulse
Anna Bridge 186:707f6e361f3e 379 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 380 }
Anna Bridge 186:707f6e361f3e 381
Anna Bridge 186:707f6e361f3e 382 return E_NO_ERROR;
Anna Bridge 186:707f6e361f3e 383 }
Anna Bridge 186:707f6e361f3e 384
Anna Bridge 186:707f6e361f3e 385 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 386 int OWM_SkipROM(mxc_owm_regs_t *owm)
Anna Bridge 186:707f6e361f3e 387 {
Anna Bridge 186:707f6e361f3e 388 // Send reset and wait for presence pulse
Anna Bridge 186:707f6e361f3e 389 if(OWM_Reset(owm))
Anna Bridge 186:707f6e361f3e 390 {
Anna Bridge 186:707f6e361f3e 391 // Send skip ROM command code
Anna Bridge 186:707f6e361f3e 392 return OWM_WriteByte(owm, SKIP_ROM_COMMAND);
Anna Bridge 186:707f6e361f3e 393 }
Anna Bridge 186:707f6e361f3e 394 else
Anna Bridge 186:707f6e361f3e 395 {
Anna Bridge 186:707f6e361f3e 396 // No presence pulse
Anna Bridge 186:707f6e361f3e 397 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 398 }
Anna Bridge 186:707f6e361f3e 399 }
Anna Bridge 186:707f6e361f3e 400
Anna Bridge 186:707f6e361f3e 401 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 402 int OWM_ODSkipROM(mxc_owm_regs_t *owm)
Anna Bridge 186:707f6e361f3e 403 {
Anna Bridge 186:707f6e361f3e 404 // Set to standard speed
Anna Bridge 186:707f6e361f3e 405 owm->cfg &= ~(MXC_F_OWM_CFG_OVERDRIVE);
Anna Bridge 186:707f6e361f3e 406
Anna Bridge 186:707f6e361f3e 407 // Send reset and wait for presence pulse
Anna Bridge 186:707f6e361f3e 408 if(OWM_Reset(owm))
Anna Bridge 186:707f6e361f3e 409 {
Anna Bridge 186:707f6e361f3e 410 // Send Overdrive skip ROM command code
Anna Bridge 186:707f6e361f3e 411 if(OWM_WriteByte(owm, OD_SKIP_ROM_COMMAND) == E_NO_ERROR)
Anna Bridge 186:707f6e361f3e 412 {
Anna Bridge 186:707f6e361f3e 413 // Set overdrive speed
Anna Bridge 186:707f6e361f3e 414 owm->cfg |= MXC_F_OWM_CFG_OVERDRIVE;
Anna Bridge 186:707f6e361f3e 415
Anna Bridge 186:707f6e361f3e 416 return E_NO_ERROR;
Anna Bridge 186:707f6e361f3e 417 }
Anna Bridge 186:707f6e361f3e 418 else
Anna Bridge 186:707f6e361f3e 419 {
Anna Bridge 186:707f6e361f3e 420 // Write failed
Anna Bridge 186:707f6e361f3e 421 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 422 }
Anna Bridge 186:707f6e361f3e 423 }
Anna Bridge 186:707f6e361f3e 424 else
Anna Bridge 186:707f6e361f3e 425 {
Anna Bridge 186:707f6e361f3e 426 // No presence pulse
Anna Bridge 186:707f6e361f3e 427 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 428 }
Anna Bridge 186:707f6e361f3e 429 }
Anna Bridge 186:707f6e361f3e 430
Anna Bridge 186:707f6e361f3e 431 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 432 int OWM_Resume(mxc_owm_regs_t *owm)
Anna Bridge 186:707f6e361f3e 433 {
Anna Bridge 186:707f6e361f3e 434 // Send reset and wait for presence pulse
Anna Bridge 186:707f6e361f3e 435 if(OWM_Reset(owm))
Anna Bridge 186:707f6e361f3e 436 {
Anna Bridge 186:707f6e361f3e 437 // Send resume command code
Anna Bridge 186:707f6e361f3e 438 return OWM_WriteByte(owm, RESUME_COMMAND);
Anna Bridge 186:707f6e361f3e 439 }
Anna Bridge 186:707f6e361f3e 440 else
Anna Bridge 186:707f6e361f3e 441 {
Anna Bridge 186:707f6e361f3e 442 // No presence pulse
Anna Bridge 186:707f6e361f3e 443 return E_COMM_ERR;
Anna Bridge 186:707f6e361f3e 444 }
Anna Bridge 186:707f6e361f3e 445 }
Anna Bridge 186:707f6e361f3e 446
Anna Bridge 186:707f6e361f3e 447 /* ************************************************************************* */
Anna Bridge 186:707f6e361f3e 448 int OWM_SearchROM(mxc_owm_regs_t *owm, int newSearch, uint8_t* ROMCode)
Anna Bridge 186:707f6e361f3e 449 {
Anna Bridge 186:707f6e361f3e 450 int nibble_start_bit = 1;
Anna Bridge 186:707f6e361f3e 451 int rom_byte_number = 0;
Anna Bridge 186:707f6e361f3e 452 uint8_t rom_nibble_mask = 0x0F;
Anna Bridge 186:707f6e361f3e 453 uint8_t search_direction = 0;
Anna Bridge 186:707f6e361f3e 454 int readValue = 0;
Anna Bridge 186:707f6e361f3e 455 int sentBits = 0;
Anna Bridge 186:707f6e361f3e 456 int discrepancy = 0;
Anna Bridge 186:707f6e361f3e 457 int bit_position = 0;
Anna Bridge 186:707f6e361f3e 458 int discrepancy_mask = 0;
Anna Bridge 186:707f6e361f3e 459 int last_zero = 0;
Anna Bridge 186:707f6e361f3e 460 uint8_t crc8 = 0;
Anna Bridge 186:707f6e361f3e 461 int search_result = 0;
Anna Bridge 186:707f6e361f3e 462
Anna Bridge 186:707f6e361f3e 463 // Clear ROM array
Anna Bridge 186:707f6e361f3e 464 memset(ROMCode, 0x0, 8);
Anna Bridge 186:707f6e361f3e 465
Anna Bridge 186:707f6e361f3e 466 if(newSearch)
Anna Bridge 186:707f6e361f3e 467 {
Anna Bridge 186:707f6e361f3e 468 // Reset all global variables to start search from begining
Anna Bridge 186:707f6e361f3e 469 LastDiscrepancy = 0;
Anna Bridge 186:707f6e361f3e 470 LastDeviceFlag = 0;
Anna Bridge 186:707f6e361f3e 471 }
Anna Bridge 186:707f6e361f3e 472
Anna Bridge 186:707f6e361f3e 473 // Check if the last call was the last device
Anna Bridge 186:707f6e361f3e 474 if(LastDeviceFlag)
Anna Bridge 186:707f6e361f3e 475 {
Anna Bridge 186:707f6e361f3e 476 // Reset the search
Anna Bridge 186:707f6e361f3e 477 LastDiscrepancy = 0;
Anna Bridge 186:707f6e361f3e 478 LastDeviceFlag = 0;
Anna Bridge 186:707f6e361f3e 479 return 0;
Anna Bridge 186:707f6e361f3e 480 }
Anna Bridge 186:707f6e361f3e 481
Anna Bridge 186:707f6e361f3e 482 // Send reset and wait for presence pulse
Anna Bridge 186:707f6e361f3e 483 if (OWM_Reset(owm))
Anna Bridge 186:707f6e361f3e 484 {
Anna Bridge 186:707f6e361f3e 485 // Send the search command
Anna Bridge 186:707f6e361f3e 486 OWM_WriteByte(owm, SEARCH_ROM_COMMAND);
Anna Bridge 186:707f6e361f3e 487
Anna Bridge 186:707f6e361f3e 488 // Set search ROM accelerator bit
Anna Bridge 186:707f6e361f3e 489 owm->ctrl_stat |= MXC_F_OWM_CTRL_STAT_SRA_MODE;
Anna Bridge 186:707f6e361f3e 490
Anna Bridge 186:707f6e361f3e 491 // Loop until through all ROM bytes 0-7 (this loops 2 times per byte)
Anna Bridge 186:707f6e361f3e 492 while(rom_byte_number < 8)
Anna Bridge 186:707f6e361f3e 493 {
Anna Bridge 186:707f6e361f3e 494 // Each loop finds the discrepancy bits and finds 4 bits (nibble) of the ROM
Anna Bridge 186:707f6e361f3e 495
Anna Bridge 186:707f6e361f3e 496 // Set the search direction the same as last time for the nibble masked
Anna Bridge 186:707f6e361f3e 497 search_direction = ROMCode[rom_byte_number] & rom_nibble_mask;
Anna Bridge 186:707f6e361f3e 498
Anna Bridge 186:707f6e361f3e 499 // If the upper nibble is the mask then shift bits to lower nibble
Anna Bridge 186:707f6e361f3e 500 if(rom_nibble_mask > 0x0F) {
Anna Bridge 186:707f6e361f3e 501 search_direction = search_direction >> 4;
Anna Bridge 186:707f6e361f3e 502 }
Anna Bridge 186:707f6e361f3e 503
Anna Bridge 186:707f6e361f3e 504 // Get the last discrepancy bit position relative to the nibble start bit
Anna Bridge 186:707f6e361f3e 505 bit_position = LastDiscrepancy - nibble_start_bit;
Anna Bridge 186:707f6e361f3e 506
Anna Bridge 186:707f6e361f3e 507 // Check if last discrepancy is witin this nibble
Anna Bridge 186:707f6e361f3e 508 if( (bit_position >= 0) && (bit_position < 4) )
Anna Bridge 186:707f6e361f3e 509 {
Anna Bridge 186:707f6e361f3e 510 // Last discrepancy is within this nibble
Anna Bridge 186:707f6e361f3e 511 // Set the bit of the last discrepancy bit
Anna Bridge 186:707f6e361f3e 512 search_direction |= (1 << (bit_position));
Anna Bridge 186:707f6e361f3e 513 }
Anna Bridge 186:707f6e361f3e 514
Anna Bridge 186:707f6e361f3e 515 // Performs two read bits and a write bit for 4 bits of the ROM
Anna Bridge 186:707f6e361f3e 516 readValue = OWM_TouchByte(owm, search_direction);
Anna Bridge 186:707f6e361f3e 517 // Get discrepancy flags
Anna Bridge 186:707f6e361f3e 518 discrepancy = readValue & 0xF;
Anna Bridge 186:707f6e361f3e 519 // Get the 4 bits sent to select the ROM
Anna Bridge 186:707f6e361f3e 520 sentBits = (readValue >> 4) & 0xF;
Anna Bridge 186:707f6e361f3e 521
Anna Bridge 186:707f6e361f3e 522 // Store the bit location of the MSB discrepancy with sentbit = 0
Anna Bridge 186:707f6e361f3e 523 if(discrepancy)
Anna Bridge 186:707f6e361f3e 524 {
Anna Bridge 186:707f6e361f3e 525 // Initialize bit_position to MSB of nibble
Anna Bridge 186:707f6e361f3e 526 bit_position = 3;
Anna Bridge 186:707f6e361f3e 527
Anna Bridge 186:707f6e361f3e 528 while(bit_position >= 0)
Anna Bridge 186:707f6e361f3e 529 {
Anna Bridge 186:707f6e361f3e 530 // Get discrepancy flag of the current bit position
Anna Bridge 186:707f6e361f3e 531 discrepancy_mask = discrepancy & (1 << bit_position);
Anna Bridge 186:707f6e361f3e 532
Anna Bridge 186:707f6e361f3e 533 // If there is a discrepancy and the sent bit is 0 save this bit position
Anna Bridge 186:707f6e361f3e 534 if( (discrepancy_mask) && !(sentBits & discrepancy_mask))
Anna Bridge 186:707f6e361f3e 535 {
Anna Bridge 186:707f6e361f3e 536 last_zero = nibble_start_bit + bit_position;
Anna Bridge 186:707f6e361f3e 537 break;
Anna Bridge 186:707f6e361f3e 538 }
Anna Bridge 186:707f6e361f3e 539
Anna Bridge 186:707f6e361f3e 540 bit_position--;
Anna Bridge 186:707f6e361f3e 541 }
Anna Bridge 186:707f6e361f3e 542 }
Anna Bridge 186:707f6e361f3e 543
Anna Bridge 186:707f6e361f3e 544 // Clear the nibble
Anna Bridge 186:707f6e361f3e 545 ROMCode[rom_byte_number] &= ~rom_nibble_mask;
Anna Bridge 186:707f6e361f3e 546
Anna Bridge 186:707f6e361f3e 547 // Store the sentBits in the ROMCode
Anna Bridge 186:707f6e361f3e 548 if(rom_nibble_mask > 0x0F) {
Anna Bridge 186:707f6e361f3e 549 ROMCode[rom_byte_number] |= (sentBits << 4);
Anna Bridge 186:707f6e361f3e 550 }
Anna Bridge 186:707f6e361f3e 551 else {
Anna Bridge 186:707f6e361f3e 552 ROMCode[rom_byte_number] |= sentBits;
Anna Bridge 186:707f6e361f3e 553 }
Anna Bridge 186:707f6e361f3e 554
Anna Bridge 186:707f6e361f3e 555 // Increment the nibble start bit and shift mask
Anna Bridge 186:707f6e361f3e 556 nibble_start_bit += 4;
Anna Bridge 186:707f6e361f3e 557 rom_nibble_mask <<= 4;
Anna Bridge 186:707f6e361f3e 558
Anna Bridge 186:707f6e361f3e 559 // If the mask is 0 then go to new ROM byte rom_byte_number and reset mask
Anna Bridge 186:707f6e361f3e 560 if (rom_nibble_mask == 0)
Anna Bridge 186:707f6e361f3e 561 {
Anna Bridge 186:707f6e361f3e 562 rom_byte_number++;
Anna Bridge 186:707f6e361f3e 563 rom_nibble_mask = 0x0F;
Anna Bridge 186:707f6e361f3e 564 }
Anna Bridge 186:707f6e361f3e 565
Anna Bridge 186:707f6e361f3e 566 } // End while(rom_byte_number < 8)
Anna Bridge 186:707f6e361f3e 567
Anna Bridge 186:707f6e361f3e 568 // Clear search ROM accelerator
Anna Bridge 186:707f6e361f3e 569 owm->ctrl_stat &= ~(MXC_F_OWM_CTRL_STAT_SRA_MODE);
Anna Bridge 186:707f6e361f3e 570
Anna Bridge 186:707f6e361f3e 571 // Calculate CRC to verify ROM code is correct
Anna Bridge 186:707f6e361f3e 572 crc8 = CalculateCRC8(ROMCode, 7);
Anna Bridge 186:707f6e361f3e 573
Anna Bridge 186:707f6e361f3e 574 // If the search was successful then
Anna Bridge 186:707f6e361f3e 575 if ((nibble_start_bit >= 65) && (crc8 == ROMCode[7]))
Anna Bridge 186:707f6e361f3e 576 {
Anna Bridge 186:707f6e361f3e 577 // Search successful so set LastDiscrepancy,LastDeviceFlag,search_result
Anna Bridge 186:707f6e361f3e 578 LastDiscrepancy = last_zero;
Anna Bridge 186:707f6e361f3e 579
Anna Bridge 186:707f6e361f3e 580 // Check for last device
Anna Bridge 186:707f6e361f3e 581 if (LastDiscrepancy == 0) {
Anna Bridge 186:707f6e361f3e 582 LastDeviceFlag = 1;
Anna Bridge 186:707f6e361f3e 583 }
Anna Bridge 186:707f6e361f3e 584
Anna Bridge 186:707f6e361f3e 585 search_result = 1;
Anna Bridge 186:707f6e361f3e 586 }
Anna Bridge 186:707f6e361f3e 587 } // End if (OWM_Reset)
Anna Bridge 186:707f6e361f3e 588
Anna Bridge 186:707f6e361f3e 589 // If no device found then reset counters so next 'search' will be like a first
Anna Bridge 186:707f6e361f3e 590 if (!search_result || !ROMCode[0])
Anna Bridge 186:707f6e361f3e 591 {
Anna Bridge 186:707f6e361f3e 592 LastDiscrepancy = 0;
Anna Bridge 186:707f6e361f3e 593 LastDeviceFlag = 0;
Anna Bridge 186:707f6e361f3e 594 search_result = 0;
Anna Bridge 186:707f6e361f3e 595 }
Anna Bridge 186:707f6e361f3e 596
Anna Bridge 186:707f6e361f3e 597 return search_result;
Anna Bridge 186:707f6e361f3e 598 }
Anna Bridge 186:707f6e361f3e 599
Anna Bridge 186:707f6e361f3e 600 /*
Anna Bridge 186:707f6e361f3e 601 * Calcualate CRC8 of the buffer of data provided
Anna Bridge 186:707f6e361f3e 602 */
Anna Bridge 186:707f6e361f3e 603 uint8_t CalculateCRC8(uint8_t* data, int len)
Anna Bridge 186:707f6e361f3e 604 {
Anna Bridge 186:707f6e361f3e 605 int i;
Anna Bridge 186:707f6e361f3e 606 uint8_t crc = 0;
Anna Bridge 186:707f6e361f3e 607
Anna Bridge 186:707f6e361f3e 608 for(i = 0; i < len; i++)
Anna Bridge 186:707f6e361f3e 609 {
Anna Bridge 186:707f6e361f3e 610 crc = update_crc8(crc, data[i]);
Anna Bridge 186:707f6e361f3e 611 }
Anna Bridge 186:707f6e361f3e 612
Anna Bridge 186:707f6e361f3e 613 return crc;
Anna Bridge 186:707f6e361f3e 614 }
Anna Bridge 186:707f6e361f3e 615
Anna Bridge 186:707f6e361f3e 616 /*
Anna Bridge 186:707f6e361f3e 617 * Calculate the CRC8 of the byte value provided with the current crc value
Anna Bridge 186:707f6e361f3e 618 * provided Returns updated crc value
Anna Bridge 186:707f6e361f3e 619 */
Anna Bridge 186:707f6e361f3e 620 uint8_t update_crc8(uint8_t crc, uint8_t val)
Anna Bridge 186:707f6e361f3e 621 {
Anna Bridge 186:707f6e361f3e 622 uint8_t inc, tmp;
Anna Bridge 186:707f6e361f3e 623
Anna Bridge 186:707f6e361f3e 624 for (inc = 0; inc < 8; inc++)
Anna Bridge 186:707f6e361f3e 625 {
Anna Bridge 186:707f6e361f3e 626 tmp = (uint8_t)(crc << 7); // Save X7 bit value
Anna Bridge 186:707f6e361f3e 627 crc >>= 1; // Shift crc
Anna Bridge 186:707f6e361f3e 628 if (((tmp >> 7) ^ (val & 0x01)) == 1) // If X7 xor X8 (input data)
Anna Bridge 186:707f6e361f3e 629 {
Anna Bridge 186:707f6e361f3e 630 crc ^= 0x8c; // XOR crc with X4 and X5, X1 = X7^X8
Anna Bridge 186:707f6e361f3e 631 crc |= 0x80; // Carry
Anna Bridge 186:707f6e361f3e 632 }
Anna Bridge 186:707f6e361f3e 633 val >>= 1;
Anna Bridge 186:707f6e361f3e 634 }
Anna Bridge 186:707f6e361f3e 635
Anna Bridge 186:707f6e361f3e 636 return crc;
Anna Bridge 186:707f6e361f3e 637 }
Anna Bridge 186:707f6e361f3e 638
Anna Bridge 186:707f6e361f3e 639 /**@} end of group owm */