mbed library sources
Dependents: frdm_kl05z_gpio_test
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Diff: targets/hal/TARGET_NXP/TARGET_LPC23XX/can_api.c
- Revision:
- 13:0645d8841f51
- Parent:
- 10:3bc89ef62ce7
- Child:
- 41:e8b66477f5bf
diff -r 5fa2273de5db -r 0645d8841f51 targets/hal/TARGET_NXP/TARGET_LPC23XX/can_api.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/hal/TARGET_NXP/TARGET_LPC23XX/can_api.c Mon Aug 05 14:12:34 2013 +0300 @@ -0,0 +1,297 @@ +/* mbed Microcontroller Library + * Copyright (c) 2006-2013 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +#include "can_api.h" +#include "cmsis.h" +#include "pinmap.h" +#include "error.h" + +#include <math.h> +#include <string.h> + +/* Acceptance filter mode in AFMR register */ +#define ACCF_OFF 0x01 +#define ACCF_BYPASS 0x02 +#define ACCF_ON 0x00 +#define ACCF_FULLCAN 0x04 + +/* There are several bit timing calculators on the internet. +http://www.port.de/engl/canprod/sv_req_form.html +http://www.kvaser.com/can/index.htm +*/ + +static const PinMap PinMap_CAN_RD[] = { + {P0_0 , CAN_1, 1}, + {P0_4 , CAN_2, 2}, + {P0_21, CAN_1, 3}, + {P2_7 , CAN_2, 1}, + {NC , NC , 0} +}; + +static const PinMap PinMap_CAN_TD[] = { + {P0_1 , CAN_1, 1}, + {P0_5 , CAN_2, 2}, + {P0_22, CAN_1, 3}, + {P2_8 , CAN_2, 1}, + {NC , NC , 0} +}; + +// Type definition to hold a CAN message +struct CANMsg { + unsigned int reserved1 : 16; + unsigned int dlc : 4; // Bits 16..19: DLC - Data Length Counter + unsigned int reserved0 : 10; + unsigned int rtr : 1; // Bit 30: Set if this is a RTR message + unsigned int type : 1; // Bit 31: Set if this is a 29-bit ID message + unsigned int id; // CAN Message ID (11-bit or 29-bit) + unsigned char data[8]; // CAN Message Data Bytes 0-7 +}; +typedef struct CANMsg CANMsg; + +static uint32_t can_disable(can_t *obj) { + uint32_t sm = obj->dev->MOD; + obj->dev->MOD |= 1; + return sm; +} + +static inline void can_enable(can_t *obj) { + if (obj->dev->MOD & 1) { + obj->dev->MOD &= ~(1); + } +} + +static int can_pclk(can_t *obj) { + int value = 0; + switch ((int)obj->dev) { + case CAN_1: value = (LPC_SC->PCLKSEL0 & (0x3 << 26)) >> 26; break; + case CAN_2: value = (LPC_SC->PCLKSEL0 & (0x3 << 28)) >> 28; break; + } + + switch (value) { + case 1: return 1; + case 2: return 2; + case 3: return 6; + default: return 4; + } +} + +// This table has the sampling points as close to 75% as possible. The first +// value is TSEG1, the second TSEG2. +static const int timing_pts[23][2] = { + {0x0, 0x0}, // 2, 50% + {0x1, 0x0}, // 3, 67% + {0x2, 0x0}, // 4, 75% + {0x3, 0x0}, // 5, 80% + {0x3, 0x1}, // 6, 67% + {0x4, 0x1}, // 7, 71% + {0x5, 0x1}, // 8, 75% + {0x6, 0x1}, // 9, 78% + {0x6, 0x2}, // 10, 70% + {0x7, 0x2}, // 11, 73% + {0x8, 0x2}, // 12, 75% + {0x9, 0x2}, // 13, 77% + {0x9, 0x3}, // 14, 71% + {0xA, 0x3}, // 15, 73% + {0xB, 0x3}, // 16, 75% + {0xC, 0x3}, // 17, 76% + {0xD, 0x3}, // 18, 78% + {0xD, 0x4}, // 19, 74% + {0xE, 0x4}, // 20, 75% + {0xF, 0x4}, // 21, 76% + {0xF, 0x5}, // 22, 73% + {0xF, 0x6}, // 23, 70% + {0xF, 0x7}, // 24, 67% +}; + +static unsigned int can_speed(unsigned int sclk, unsigned int pclk, unsigned int cclk, unsigned char psjw) { + uint32_t btr; + uint16_t brp = 0; + uint32_t calcbit; + uint32_t bitwidth; + int hit = 0; + int bits; + + bitwidth = sclk / (pclk * cclk); + + brp = bitwidth / 0x18; + while ((!hit) && (brp < bitwidth / 4)) { + brp++; + for (bits = 22; bits > 0; bits--) { + calcbit = (bits + 3) * (brp + 1); + if (calcbit == bitwidth) { + hit = 1; + break; + } + } + } + + if (hit) { + btr = ((timing_pts[bits][1] << 20) & 0x00700000) + | ((timing_pts[bits][0] << 16) & 0x000F0000) + | ((psjw << 14) & 0x0000C000) + | ((brp << 0) & 0x000003FF); + } else { + btr = 0xFFFFFFFF; + } + + return btr; +} + +void can_init(can_t *obj, PinName rd, PinName td) { + CANName can_rd = (CANName)pinmap_peripheral(rd, PinMap_CAN_RD); + CANName can_td = (CANName)pinmap_peripheral(td, PinMap_CAN_TD); + obj->dev = (LPC_CAN_TypeDef *)pinmap_merge(can_rd, can_td); + if ((int)obj->dev == NC) { + error("CAN pin mapping failed"); + } + + switch ((int)obj->dev) { + case CAN_1: LPC_SC->PCONP |= 1 << 13; break; + case CAN_2: LPC_SC->PCONP |= 1 << 14; break; + } + + pinmap_pinout(rd, PinMap_CAN_RD); + pinmap_pinout(td, PinMap_CAN_TD); + + can_reset(obj); + obj->dev->IER = 0; // Disable Interrupts + can_frequency(obj, 100000); + + LPC_CANAF->AFMR = ACCF_BYPASS; // Bypass Filter +} + +void can_free(can_t *obj) { + switch ((int)obj->dev) { + case CAN_1: LPC_SC->PCONP &= ~(1 << 13); break; + case CAN_2: LPC_SC->PCONP &= ~(1 << 14); break; + } +} + +int can_frequency(can_t *obj, int f) { + int pclk = can_pclk(obj); + int btr = can_speed(SystemCoreClock, pclk, (unsigned int)f, 1); + + if (btr > 0) { + uint32_t modmask = can_disable(obj); + obj->dev->BTR = btr; + obj->dev->MOD = modmask; + return 1; + } else { + return 0; + } +} + +int can_write(can_t *obj, CAN_Message msg, int cc) { + unsigned int CANStatus; + CANMsg m; + + can_enable(obj); + + m.id = msg.id ; + m.dlc = msg.len & 0xF; + m.rtr = msg.type; + m.type = msg.format; + memcpy(m.data, msg.data, msg.len); + const unsigned int *buf = (const unsigned int *)&m; + + CANStatus = obj->dev->SR; + if (CANStatus & 0x00000004) { + obj->dev->TFI1 = buf[0] & 0xC00F0000; + obj->dev->TID1 = buf[1]; + obj->dev->TDA1 = buf[2]; + obj->dev->TDB1 = buf[3]; + if (cc) { + obj->dev->CMR = 0x30; + } else { + obj->dev->CMR = 0x21; + } + return 1; + + } else if (CANStatus & 0x00000400) { + obj->dev->TFI2 = buf[0] & 0xC00F0000; + obj->dev->TID2 = buf[1]; + obj->dev->TDA2 = buf[2]; + obj->dev->TDB2 = buf[3]; + if (cc) { + obj->dev->CMR = 0x50; + } else { + obj->dev->CMR = 0x41; + } + return 1; + + } else if (CANStatus & 0x00040000) { + obj->dev->TFI3 = buf[0] & 0xC00F0000; + obj->dev->TID3 = buf[1]; + obj->dev->TDA3 = buf[2]; + obj->dev->TDB3 = buf[3]; + if (cc) { + obj->dev->CMR = 0x90; + } else { + obj->dev->CMR = 0x81; + } + return 1; + } + + return 0; +} + +int can_read(can_t *obj, CAN_Message *msg) { + CANMsg x; + unsigned int *i = (unsigned int *)&x; + + can_enable(obj); + + if (obj->dev->GSR & 0x1) { + *i++ = obj->dev->RFS; // Frame + *i++ = obj->dev->RID; // ID + *i++ = obj->dev->RDA; // Data A + *i++ = obj->dev->RDB; // Data B + obj->dev->CMR = 0x04; // release receive buffer + + msg->id = x.id; + msg->len = x.dlc; + msg->format = (x.type)? CANExtended : CANStandard; + msg->type = (x.rtr)? CANRemote: CANData; + memcpy(msg->data,x.data,x.dlc); + return 1; + } + + return 0; +} + +void can_reset(can_t *obj) { + can_disable(obj); + obj->dev->GSR = 0; // Reset error counter when CAN1MOD is in reset +} + +unsigned char can_rderror(can_t *obj) { + return (obj->dev->GSR >> 16) & 0xFF; +} + +unsigned char can_tderror(can_t *obj) { + return (obj->dev->GSR >> 24) & 0xFF; +} + +void can_monitor(can_t *obj, int silent) { + uint32_t mod_mask = can_disable(obj); + if (silent) { + obj->dev->MOD |= (1 << 1); + } else { + obj->dev->MOD &= ~(1 << 1); + } + if (!(mod_mask & 1)) { + can_enable(obj); + } +}