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