Umar Naeem
mbed library sources. Supersedes mbed-src.
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mbed-dev
by 
Umar Naeem
Diff: targets/TARGET_NXP/TARGET_LPC23XX/can_api.c
- Revision:
- 149:156823d33999
- Parent:
- 144:ef7eb2e8f9f7
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC23XX/can_api.c Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,303 @@
+/* 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 "mbed_assert.h"
+#include "can_api.h"
+#include "cmsis.h"
+#include "pinmap.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);
+ }
+}
+
+int can_mode(can_t *obj, CanMode mode) {
+ return 0; // not implemented
+}
+
+int can_filter(can_t *obj, uint32_t id, uint32_t mask, CANFormat format, int32_t handle) {
+ return 0; // not implemented
+}
+
+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);
+ MBED_ASSERT((int)obj->dev != NC);
+
+ 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, int handle) {
+ 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);
+ }
+}