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abstract crc function (#448)

This commit is contained in:
rbiasini 2020-02-24 15:26:59 -08:00 committed by GitHub
parent 1b49d3e830
commit 96e535e5a0
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 21 additions and 22 deletions
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16
board/crc.h Normal file
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@ -0,0 +1,16 @@
uint8_t crc_checksum(uint8_t *dat, int len, const uint8_t poly) {
uint8_t crc = 0xFF;
int i, j;
for (i = len - 1; i >= 0; i--) {
crc ^= dat[i];
for (j = 0; j < 8; j++) {
if ((crc & 0x80U) != 0U) {
crc = (uint8_t)((crc << 1) ^ poly);
}
else {
crc <<= 1;
}
}
}
return crc;
}

27
board/pedal/main.c
View File

@ -19,6 +19,7 @@
#include "drivers/timer.h"
#include "gpio.h"
#include "crc.h"
#define CAN CAN1
@ -105,26 +106,6 @@ int usb_cb_control_msg(USB_Setup_TypeDef *setup, uint8_t *resp, bool hardwired)
#endif
// ***************************** pedal can checksum *****************************
uint8_t pedal_checksum(uint8_t *dat, int len) {
uint8_t crc = 0xFF;
uint8_t poly = 0xD5; // standard crc8
int i, j;
for (i = len - 1; i >= 0; i--) {
crc ^= dat[i];
for (j = 0; j < 8; j++) {
if ((crc & 0x80U) != 0U) {
crc = (uint8_t)((crc << 1) ^ poly);
}
else {
crc <<= 1;
}
}
}
return crc;
}
// ***************************** can port *****************************
// addresses to be used on CAN
@ -155,6 +136,8 @@ uint32_t current_index = 0;
#define FAULT_INVALID 6U
uint8_t state = FAULT_STARTUP;
const uint8_t crc_poly = 0xD5; // standard crc8
void CAN1_RX0_IRQ_Handler(void) {
while ((CAN->RF0R & CAN_RF0R_FMP0) != 0) {
#ifdef DEBUG
@ -184,7 +167,7 @@ void CAN1_RX0_IRQ_Handler(void) {
uint16_t value_1 = (dat[2] << 8) | dat[3];
bool enable = ((dat[4] >> 7) & 1U) != 0U;
uint8_t index = dat[4] & COUNTER_CYCLE;
if (pedal_checksum(dat, CAN_GAS_SIZE - 1) == dat[5]) {
if (crc_checksum(dat, CAN_GAS_SIZE - 1, crc_poly) == dat[5]) {
if (((current_index + 1U) & COUNTER_CYCLE) == index) {
#ifdef DEBUG
puts("setting gas ");
@ -247,7 +230,7 @@ void TIM3_IRQ_Handler(void) {
dat[2] = (pdl1 >> 8) & 0xFFU;
dat[3] = (pdl1 >> 0) & 0xFFU;
dat[4] = ((state & 0xFU) << 4) | pkt_idx;
dat[5] = pedal_checksum(dat, CAN_GAS_SIZE - 1);
dat[5] = crc_checksum(dat, CAN_GAS_SIZE - 1, crc_poly);
CAN->sTxMailBox[0].TDLR = dat[0] | (dat[1] << 8) | (dat[2] << 16) | (dat[3] << 24);
CAN->sTxMailBox[0].TDHR = dat[4] | (dat[5] << 8);
CAN->sTxMailBox[0].TDTR = 6; // len of packet is 5