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slcan.c
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slcan.c
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/*
* slcan.c
*
* Created on: 01.06.2018
* Author: tixiv
*/
#include "slcan.h"
static uint8_t read_hex_number_8(const char * str, uint8_t len){
uint8_t d = 0;
while(len--){
d <<= 4;
uint8_t v = 0;
if((*str >= '0') && (*str <= '9')) v = *str - '0';
else if((*str >= 'A') && (*str <= 'F')) v = *str - 'A' + 10;
else if((*str >= 'a') && (*str <= 'f')) v = *str - 'a' + 10;
d |= v;
str++;
}
return d;
}
static uint32_t read_hex_number(const char * str, uint8_t len){
uint32_t d = 0;
while(len--){
d <<= 4;
uint8_t v = 0;
if((*str >= '0') && (*str <= '9')) v = *str - '0';
else if((*str >= 'A') && (*str <= 'F')) v = *str - 'A' + 10;
else if((*str >= 'a') && (*str <= 'f')) v = *str - 'a' + 10;
d |= v;
str++;
}
return d;
}
static bool send_can_message_from_string(slcan_t * lp, const char * str){
char cmd = *str++; // command char
bool IDE = cmd == 'T' || cmd == 'R'; // upercase means EID
bool RTR = cmd == 'r' || cmd == 'R'; // the upper or lowercase r means RTR
uint32_t id;
uint8_t dlc;
if(!IDE){ //standard identifier
id = read_hex_number(str, 3);
str += 3;
if(id > 0x7ff) return false;
}else{
id = read_hex_number(str, 8);
str += 8;
if(id > 0x1fffffff) return false;
}
dlc = read_hex_number_8(str, 1);
str += 1;
if(dlc > 8)
return false;
can_message_t * cmsg = lp->can_buffer_get_callback();
cmsg->RTR = RTR;
cmsg->IDE = IDE;
cmsg->dlc = dlc;
cmsg->id = id;
if(!RTR){
for(uint8_t i = 0; i < dlc; i++){
cmsg->data[i] = read_hex_number_8(str, 2);
str += 2;
}
}
lp->can_transmit_callback(cmsg);
return true;
}
bool slcan_can_message_from_string(can_message_t * cmsg, const char * str){
char cmd = *str++; // command char
if(cmd != 't' && cmd != 'T' && cmd != 'r' && cmd != 'R')
return false;
bool IDE = cmd == 'T' || cmd == 'R'; // upercase means EID
bool RTR = cmd == 'r' || cmd == 'R'; // the upper or lowercase r means RTR
uint32_t id;
uint8_t dlc;
if(!IDE){ //standard identifier
id = read_hex_number(str, 3);
str += 3;
if(id > 0x7ff) return false;
}else{
id = read_hex_number(str, 8);
str += 8;
if(id > 0x1fffffff) return false;
}
dlc = read_hex_number_8(str, 1);
str += 1;
if(dlc > 8)
return false;
cmsg->RTR = RTR;
cmsg->IDE = IDE;
cmsg->dlc = dlc;
cmsg->id = id;
if(!RTR){
for(uint8_t i = 0; i < dlc; i++){
cmsg->data[i] = read_hex_number_8(str, 2);
str += 2;
}
}
return true;
}
static char * put_hex_byte(char * str, uint8_t val);
static void execute_status_command(slcan_t * lp){
uint8_t s = lp->can_get_status_callback();
char buf[5];
char * str = buf;
*str++ = 'F';
str = put_hex_byte(str, s);
*str++ = '\r';
*str++ = 0;
lp->uart_putstr_callback(buf);
}
void slcan_execute_command(slcan_t * lp, const char * str){
switch(str[0]){
case 't': // transmit standard ID messages
case 'r':
if(lp->transmit_enabled && send_can_message_from_string(lp, str)){
lp->uart_putstr_callback("z\r");
}else{
lp->uart_putstr_callback("\a"); // bell
}
break;
case 'T': // transmit extended ID messages
case 'R':
if(lp->transmit_enabled && send_can_message_from_string(lp, str)){
lp->uart_putstr_callback("Z\r");
}else{
lp->uart_putstr_callback("\a"); // bell
}
break;
case 'O': //open terminal
if(lp->baudrate_configured && !lp->terminal_open
&& lp->can_init_callback(can_mode_normal, lp->baud)
){
lp->terminal_open = 1;
lp->transmit_enabled = 1;
lp->uart_putstr_callback("\r");
}else{
lp->uart_putstr_callback("\a"); // bell
}
break;
case 'L': // open terminal listen only
if(lp->baudrate_configured && !lp->terminal_open
&& lp->can_init_callback(can_mode_listen, lp->baud)
){
lp->terminal_open = 1;
lp->uart_putstr_callback("\r");
}else{
lp->uart_putstr_callback("\a"); // bell
}
break;
case 'l': // (lower case L) open terminal in loopback mode (non standard feature)
if(lp->baudrate_configured && !lp->terminal_open
&& lp->can_init_callback(can_mode_loopback, lp->baud)
){
lp->terminal_open = 1;
lp->transmit_enabled = 1;
lp->uart_putstr_callback("\r");
}else{
lp->uart_putstr_callback("\a"); // bell
}
break;
case 'C': //close terminal
if(lp->terminal_open){
lp->terminal_open = 0;
lp->transmit_enabled = 0;
lp->can_init_callback(can_mode_close, 0);
lp->uart_putstr_callback("\r");
}else{
lp->uart_putstr_callback("\a"); // bell
}
break;
case 'F': // request status
execute_status_command(lp);
break;
case 'S': //select bitrate e.g. "S4" for 125kbit
if(lp->terminal_open || str[1] < '0' || str[1] == '7' || str[1] > '8') {
// 800 kBaud is not supported, and any other character is also error
// or terminal is open, we cannot set a baud rate
lp->uart_putstr_callback("\a"); // bell
} else {
lp->baudrate_configured = 1;
lp->baud = str[1] - '0';
lp->uart_putstr_callback("\r");
}
break;
case'V'://version
lp->uart_putstr_callback("V1010\r");
break;
case'N'://serial number
lp->uart_putstr_callback("N1234\r");
break;
}
}
// puts one ascii hex digit (0-9, A-F) to a string for val in range
// 0-15, returns a pointer to the next position in the string
static char * put_hex_digit(char * str, uint8_t val){
char c;
val &= 0x0f;
if(val < 10){
c = val + '0';
}else{
c = val + 'A' - 10;
}
*str++ = c;
return str;
}
// puts a byte as ascii hex to a string and returns a pointer
// to the nex position in the string.
static char * put_hex_byte(char * str, uint8_t val){
str = put_hex_digit(str, val >> 4);
str = put_hex_digit(str, val);
return str;
}
void slcan_handle_can_message(slcan_t * lp, const can_message_t *cmsg){
// cmd id dlc data \r 0
char buf[ 1 + 8 + 1 + 8*2 + 1 + 1];
char * str = buf;
if(lp->terminal_open){
if(!cmsg->IDE){ // standard identifier
*str++ = cmsg->RTR ? 'r':'t';
str = put_hex_digit(str, cmsg->id >> 8);
str = put_hex_byte(str, cmsg->id & 0xff);
}else{ // extended identifier
*str++ = cmsg->RTR ? 'R':'T';
str = put_hex_byte(str, (cmsg->id >> 24) & 0xff);
str = put_hex_byte(str, (cmsg->id >> 16) & 0xff);
str = put_hex_byte(str, (cmsg->id >> 8) & 0xff);
str = put_hex_byte(str, (cmsg->id >> 0) & 0xff);
}
str = put_hex_digit(str, cmsg->dlc);
if(!cmsg->RTR){ // no data on RTR
for(uint8_t i = 0; i < cmsg->dlc; i++){
str = put_hex_byte(str, cmsg->data[i]);
}
}
*str++ = '\r';
*str++ = 0;
lp->uart_putstr_callback(buf);
}
}
void slcan_string_from_can_message(char * str, const can_message_t *cmsg){
// cmd id dlc data \r 0
//char buf[ 1 + 8 + 1 + 8*2 + 1 + 1];
//char * str = buf;
if(!cmsg->IDE){ // standard identifier
*str++ = cmsg->RTR ? 'r':'t';
str = put_hex_digit(str, cmsg->id >> 8);
str = put_hex_byte(str, cmsg->id & 0xff);
}else{ // extended identifier
*str++ = cmsg->RTR ? 'R':'T';
str = put_hex_byte(str, (cmsg->id >> 24) & 0xff);
str = put_hex_byte(str, (cmsg->id >> 16) & 0xff);
str = put_hex_byte(str, (cmsg->id >> 8) & 0xff);
str = put_hex_byte(str, (cmsg->id >> 0) & 0xff);
}
str = put_hex_digit(str, cmsg->dlc);
if(!cmsg->RTR){ // no data on RTR
for(uint8_t i = 0; i < cmsg->dlc; i++){
str = put_hex_byte(str, cmsg->data[i]);
}
}
*str++ = '\r';
*str++ = 0;
}
const char * slcan_get_baud_string(uint32_t bps){
switch(bps){
case 10000: return "S0\r";
case 20000: return "S1\r";
case 50000: return "S2\r";
case 100000: return "S3\r";
case 125000: return "S4\r";
case 250000: return "S5\r";
case 500000: return "S6\r";
case 800000: return "S7\r";
case 1000000: return "S8\r";
}
return 0;
}