Here is the old version of the souce code called can.c.
#include <stdio.h>
#include <string.h>
#include "chip.h"
#include "bsp_conf.h"
#include "can.h"
/**
--------------------------------------------
说明:
LPC1549的can驱动程序是集成在ROM里的,不需要操作寄存器。
有32组滤波器和32个FIFO (对应CAN_MSG_OBJ结构里的msgobj)[0~31]
一组滤波器对应一个FIFO[0~31]
必须配置滤波器FIFO才能正确接收！！！
--------------------------------------------
通过配置mode_id和mask可以实现一组ID的过滤
过滤规则：
<received_mode_id> & mask == mode_id & mask
例如: Configure FIFO_1 to receive all 11-bit messages 0x400-0x4FF
msg_obj.msgobj = 1;
msg_obj.mode_id = 0x400;
msg_obj.mask = 0x700;
--------------------------------------------
强制帧类型过滤,即只有一种"帧类型"允许通过,可以通过mode_id和mask确定帧类型
mode_id: C_CAN operation mode
#define CAN_MSGOBJ_STD 0x00000000UL //CAN 2.0a 11-bit ID
#define CAN_MSGOBJ_EXT 0x20000000UL //CAN 2.0b 29-bit ID
#define CAN_MSGOBJ_DAT 0x00000000UL //data frame
#define CAN_MSGOBJ_RTR 0x40000000UL //rtr frame
mask:
bit29为1时, mask[29] & mode_id[29]确定扩展帧还是标准帧
bit30位1时, mask[30] & mode_id[30]确定数据帧还是远程帧
mask的以上两位为0时没有意义!!!
例如:
msg.msgobj = 31;
msg.mode_id = CAN_RTR_FLAG|0x00 ;
msg.mask = CAN_EFF_FLAG|0x00;
结果:
mask[29] & mode_id[29] = 0; //即标准帧
滤波器31允许所有的"标准远程帧"通过
总体来说,mask的bit29和bit30没有什么利用价值,编码时不要考虑过多!!!
只需要利用bit0~bit28即可
--------------------------------------------
--------------------------------------------
波特率计算方法:
//CAN_CLK = systemclock / (DIVVAL +1) = 12MHZ
can_config.clkdiv = 5;
//14:12(TSEG2) 11:8(TSEG1) 7:6(SJW) 5:0(BRP)
can_config.btr = 0x0502; //TSEG2=0, TSEG1=5, SJW=0, BRP=2
//计算
Bit rate = CAN_CLK/((BRP + 1) x (TSEG1+2+TSEG2+1))
= 12MHZ /((2+1) x (5+2+0+1))
= 500KHZ
Sample point = (TSEG1+2) / (TSEG1+2+TSEG2+1) x 100
= 7 / (5+2+0+1) x 100
= 87.5%(建议值)
--------------------------------------------
*/
#define MAX_FILTER_FIFO_COUNT 32 //32组滤波器(一组滤波器对应一个FIFO)
/* Memory for CAN API */
#define MAX_CAN0_PARAM_SIZE 512
static uint32_t can0_api_mem[MAX_CAN0_PARAM_SIZE]={0};
/* CAN handle */
static CAN_HANDLE_T pCan0Handle;
/* 波特率定义 */
enum
{
CAN_RATE_125K = 0x050B,
CAN_RATE_250K = 0x0505,
CAN_RATE_500K = 0x0502,
};
/* 发送FIFO忙标志 */
static uint8_t can0_tx_busy[MAX_FILTER_FIFO_COUNT] = {0};
/* CAN初始化参数 */
static can_param_t can0_param = {0};
/**
----------------------------------------
@brief 接收到数据后先进入该函数，然后根据滤波器号去对应FIFO里取数
@param[in] msg_obj FIFO号
@return none
----------------------------------------
*/
static void _can0_rx(uint8_t msg_obj)
{
//printf("%s msg_obj[%d]\r\n", __func__, msg_obj);
CAN_MSG_OBJ msg = {0};
msg.msgobj= msg_obj; //选择从哪个FIFO接收数据[0~31]
/* Now load up the msg_obj structure with the CAN message */
LPC_CAND_API->hwCAN_MsgReceive(pCan0Handle, &msg);
if(can0_param.irq_rcv)
{
can_frame_t frame = {0};
frame.can_id = msg.mode_id;
frame.can_dlc = msg.dlc;
memcpy(frame.data, msg.data, sizeof(frame.data));
can0_param.irq_rcv(frame);
}
}
/**
---------------------------------------
@brief 发送完数据后,再进入该函数
@param[in] msg_obj FIFO号
@return none
---------------------------------------
*/
static void _can0_tx(uint8_t msg_obj)
{
//printf("%s msg_obj[%d]\r\n", __func__, msg_obj);
if(msg_obj < MAX_FILTER_FIFO_COUNT)
can0_tx_busy[msg_obj] = 0;
}
/**
---------------------------------------
@brief 错误处理
@param[in] error_info 错误码
@return none
---------------------------------------
*/
static void _can0_error(uint32_t error_info)
{
if (error_info & CAN_ERROR_BOFF)
{
}
printf("%s error_info[0x%X]\r\n", __func__, error_info);
}
/**
----------------------------------------------------------
@brief can_init
@param[in] param CAN的初始化参数
@param[in] filter 滤波器配置
@param[in] len 滤波器数量
@return none
-----------------------------------------------------------
*/
void can0_init(can_param_t *param, can_filter_t *filter, int len)
{
if(param==NULL)
{
can0_param.rate = 125000;
can0_param.isIrq = 1;
can0_param.irq_rcv = NULL;
}
else
{
can0_param = *param;
}
uint32_t btr = CAN_RATE_125K;
switch(can0_param.rate)
{
case 125000 : btr = CAN_RATE_125K; break;
case 250000 : btr = CAN_RATE_250K; break;
case 500000 : btr = CAN_RATE_500K; break;
default: btr = CAN_RATE_125K; break;
}
/* Enable clocking for CAN and reset the controller */
Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_CAN);
Chip_SYSCTL_PeriphReset(RESET_CAN);
/* Assign the pins rx 0[28] and tx 0[29] */
Chip_IOCON_PinMuxSet(LPC_IOCON, 0, 28, (IOCON_MODE_INACT | IOCON_DIGMODE_EN));
Chip_IOCON_PinMuxSet(LPC_IOCON, 0, 29, (IOCON_MODE_INACT | IOCON_DIGMODE_EN));
Chip_SWM_MovablePortPinAssign(SWM_CAN_RD1_I, 0, 28); /* Rx P0.28 */
Chip_SWM_MovablePortPinAssign(SWM_CAN_TD1_O, 0, 29); /* Tx P0.29 */
/* CAN initialization structure */
CAN_CFG can_config = {0};
/* Set the Can peripheral to run at 12Mhz. Was used to calculate the btr value in next line. */
/* CPU runs from Xtal at 72Mhz so the divisor should be 6 but clkdiv is divisor - 1 */
can_config.clkdiv = 5;
/* btr values can be obtained from www.bittiming.can-wiki.info (use Bosch C_CAN / D_CAN) */
can_config.btr = btr;
can_config.isr_ena = TRUE;
/* Publish CAN Callback Functions */
CAN_CALLBACKS callbacks = {
_can0_rx,
_can0_tx,
_can0_error
};
CAN_API_INIT_PARAM_T init_param = {
.mem_base = (uint32_t)&can0_api_mem[0],
.can_reg_base = LPC_C_CAN0_BASE,
.can_cfg = &can_config,
.callbacks = &callbacks,
.canopen_cfg = NULL, //canOpen不涉及
.co_callbacks = NULL, //canOpen不涉及
};
/* Validate that we reserved enough memory */
uint32_t maxParamSize = LPC_CAND_API->hwCAN_GetMemSize(&init_param);
if (maxParamSize > MAX_CAN0_PARAM_SIZE / 4)
{
printf("can init fail\r\n");
return;
}
/* Initialize the ROM with specific configuration */
uint32_t status = LPC_CAND_API->hwCAN_Init(&pCan0Handle, &init_param);
if (status != CAN_ERROR_NONE)
{
printf("can init fail\r\n");
return;
}
if (can_config.isr_ena == TRUE)
{
NVIC_EnableIRQ(CAN_IRQn);
}
/* Config filter */
CAN_MSG_OBJ msg = {0};
if(filter==NULL)
{
for(int i=0; i<MAX_FILTER_FIFO_COUNT; i++)
{
memset(&msg, 0 ,sizeof(msg));
msg.msgobj = i;
//默认0~23处理扩展数据帧，24~31处理扩展远程帧
//msg.mode_id = i>=24? (CAN_EFF_FLAG|CAN_RTR_FLAG|0x00) : (CAN_EFF_FLAG|0x00);
msg.mode_id = (CAN_EFF_FLAG|0x00); //只接收扩展数据帧
msg.mask = 0x00;
LPC_CAND_API->hwCAN_ConfigRxmsgobj(pCan0Handle, &msg);
//printf("can init filter[%d] mode_id [0x%X] mask[0x%X]\r\n", i, msg.mode_id, msg.mask);
}
}
else
{
len = len>MAX_FILTER_FIFO_COUNT? MAX_FILTER_FIFO_COUNT : len;
for(int i=0; i<len; i++)
{
memset(&msg, 0 ,sizeof(msg));
msg.msgobj = i;
msg.mode_id = filter[i].mode_id;
msg.mask = filter[i].mask;
LPC_CAND_API->hwCAN_ConfigRxmsgobj(pCan0Handle, &msg);
//printf("can init filter[%d] mode_id [0x%X] mask[0x%X]\r\n", i, msg.mode_id, msg.mask);
}
}
}
/**
----------------------------------------------------------
@brief can_send
@param[in] frame can帧结构
@return 0(ok) -1(fail)
-----------------------------------------------------------
*/
int can0_send(can_frame_t frame)
{
int ret = -1;
CAN_MSG_OBJ msg = {0};
for(int i=0; i<MAX_FILTER_FIFO_COUNT;i++)
{
if(can0_tx_busy[i]==0)
{
msg.msgobj = i;
msg.mode_id = frame.can_id;
msg.mask = 0x00;
msg.dlc = frame.can_dlc;
memcpy(msg.data, frame.data, sizeof(msg.data));
LPC_CAND_API->hwCAN_MsgTransmit(pCan0Handle, &msg);
can0_tx_busy[i]=1;
ret = 0;
break;
}
}
return ret;
}
void CAN_IRQHandler(void)
{
LPC_CAND_API->hwCAN_Isr(pCan0Handle);
}
