From 8cc05c79cea62609d02231492c054a0cca2b2289 Mon Sep 17 00:00:00 2001 From: jaseg Date: Mon, 25 Sep 2023 23:57:36 +0200 Subject: Center firmware WIP --- center_fw/src/transmit.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 center_fw/src/transmit.c (limited to 'center_fw/src/transmit.c') diff --git a/center_fw/src/transmit.c b/center_fw/src/transmit.c new file mode 100644 index 0000000..c31c833 --- /dev/null +++ b/center_fw/src/transmit.c @@ -0,0 +1,53 @@ + +#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; +} -- cgit