minimalistic framing for UART command

copied the uart framing idea from
https://github.com/EmanuelFeru/hoverboard-firmware-hack-FOC

to use:
send $AAAA to start frame
then steer, speed as usual
and XOR($AAAA, steer, speed) as checksum

commands that don't match are ignored, and UART DMA is reset
hopefully this will set it up to catch the next one
re-send frequently.
This commit is contained in:
Elliot Williams
2019-12-16 16:11:07 +01:00
parent 2569b22640
commit 976ba2d44a
2 changed files with 17 additions and 10 deletions

View File

@ -9,6 +9,7 @@
#define DELAY_IN_MAIN_LOOP 5 // in ms. default 5. it is independent of all the timing critical stuff. do not touch if you do not know what you are doing.
#define TIMEOUT 5 // number of wrong / missing input commands before emergency off
#define START_FRAME 0xAAAA // serial command start-of-frame magic word
// ############################### GENERAL ###############################

View File

@ -41,9 +41,10 @@ int cmd2;
int cmd3;
typedef struct{
int16_t steer;
int16_t speed;
//uint32_t crc;
uint16_t start_of_frame;
int16_t steer;
int16_t speed;
uint16_t checksum;
} Serialcommand;
volatile Serialcommand command;
@ -157,7 +158,7 @@ int main(void) {
#ifdef CONTROL_SERIAL_USART2
UART_Control_Init();
HAL_UART_Receive_DMA(&huart2, (uint8_t *)&command, 4);
HAL_UART_Receive_DMA(&huart2, (uint8_t *)&command, sizeof(command));
#endif
#ifdef DEBUG_I2C_LCD
@ -218,12 +219,17 @@ int main(void) {
timeout = 0;
#endif
#ifdef CONTROL_SERIAL_USART2
cmd1 = CLAMP((int16_t)command.steer, -1000, 1000);
cmd2 = CLAMP((int16_t)command.speed, -1000, 1000);
timeout = 0;
#endif
#ifdef CONTROL_SERIAL_USART2
if (command.start_of_frame == START_FRAME && command.checksum ==
(command.start_of_frame ^ command.steer ^ command.speed)) {
cmd1 = CLAMP((int16_t)command.steer, -1000, 1000);
cmd2 = CLAMP((int16_t)command.speed, -1000, 1000);
} else { // restart DMA to hopefully get back in sync
HAL_UART_DMAStop(&huart2);
HAL_UART_Receive_DMA(&huart2, (uint8_t *)&command, sizeof(command));
}
timeout = 0;
#endif
#ifdef CONTROL_MOTOR_TEST
if (motor_test_direction == 1) cmd2 += 1;