drashna/qmk_firmware
1
0
Fork 0
Code Activity Actions

Implement receive of valid small byte stuffed frames

Browse source
This commit is contained in:
Fred Sundvik 2016-02-14 14:04:51 +02:00
parent 8a991a266e
commit ce3a21cbea
3 changed files with 95 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

36
serial_link/protocol/byte_stuffer.c
View file

@ -25,5 +25,39 @@ SOFTWARE.
#include "protocol/byte_stuffer.h"
#include "protocol/frame_validator.h"
void recv_byte(uint8_t data) {
// This implements the "Consistent overhead byte stuffing protocol"
// https://en.wikipedia.org/wiki/Consistent_Overhead_Byte_Stuffing
// http://www.stuartcheshire.org/papers/COBSforToN.pdf
typedef struct byte_stuffer_state {
uint16_t next_zero;
uint16_t data_pos;
uint8_t data[256];
}byte_stuffer_state_t;
void init_byte_stuffer_state(byte_stuffer_state_t* state) {
state->next_zero = 0;
state->data_pos = 0;
}
void recv_byte(byte_stuffer_state_t* state, uint8_t data) {
if (state->next_zero == 0) {
state->next_zero = data;
state->data_pos = 0;
return;
}
state->next_zero--;
if (data == 0) {
recv_frame(state->data, state->data_pos);
}
else {
if (state->next_zero == 0) {
state->next_zero = data;
state->data[state->data_pos++] = 0;
}
else {
state->data[state->data_pos++] = data;
}
}
}