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#include "global.h"
#include "transmit.h"
#include "8b10b.h"
struct {
uint8_t *buf;
size_t pos, len;
uint16_t current_symbol;
struct state_8b10b_enc enc;
} tx_state = {0};
volatile uint32_t tx_overflow_cnt = 0;
void tx_init(uint8_t *tx_buf) {
tx_state.buf = tx_buf;
tx_state.pos = 0;
tx_state.current_symbol = 0;
xfr_8b10b_encode_reset(&tx_state.enc);
}
int tx_transmit(size_t len) {
if (!tx_state.buf)
return TX_ERR_UNINITIALIZED;
if (tx_state.len) {
tx_overflow_cnt++;
return TX_ERR_BUSY;
}
tx_state.len = len;
tx_state.current_symbol = 1;
return 0;
}
int tx_next_bit() {
if (!tx_state.len)
return TX_IDLE;
int sym = tx_state.current_symbol;
if (sym == 1) /* We're transmitting the first bit of a new frame now. */
sym = xfr_8b10b_encode(&tx_state.enc, tx_state.buf[tx_state.pos++]) | (1<<10);
int bit = sym&1;
sym >>= 1;
if (sym == 1 && tx_state.pos == tx_state.len)
/* We're transmitting the last bit of a transmission now. Reset state. */
tx_state.pos = tx_state.len = sym = 0;
tx_state.current_symbol = sym;
return bit;
}
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