140 lines
4.2 KiB
C
Executable File
140 lines
4.2 KiB
C
Executable File
#include <stdlib.h>
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#include <string.h>
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#include "device.h"
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#include "KISS.h"
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static uint8_t serialBuffer[AX25_MAX_FRAME_LEN]; // Buffer for holding incoming serial data
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AX25Ctx *ax25ctx;
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Afsk *channel;
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Serial *serial;
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size_t frame_len;
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bool IN_FRAME;
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bool ESCAPE;
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bool FLOWCONTROL;
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uint8_t command = CMD_UNKNOWN;
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unsigned long custom_preamble = CONFIG_AFSK_PREAMBLE_LEN;
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unsigned long custom_tail = CONFIG_AFSK_TRAILER_LEN;
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unsigned long slotTime = 200;
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uint8_t p = CONFIG_CSMA_P;
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void kiss_init(AX25Ctx *ax25, Afsk *afsk, Serial *ser) {
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ax25ctx = ax25;
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serial = ser;
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channel = afsk;
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FLOWCONTROL = false;
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}
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void kiss_messageCallback(AX25Ctx *ctx) {
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fputc(FEND, &serial->uart0);
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fputc(0x00, &serial->uart0);
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for (unsigned i = 0; i < ctx->frame_len-2; i++) {
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uint8_t b = ctx->buf[i];
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if (b == FEND) {
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fputc(FESC, &serial->uart0);
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fputc(TFEND, &serial->uart0);
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} else if (b == FESC) {
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fputc(FESC, &serial->uart0);
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fputc(TFESC, &serial->uart0);
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} else {
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fputc(b, &serial->uart0);
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}
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}
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fputc(FEND, &serial->uart0);
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}
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void kiss_csma(AX25Ctx *ctx, uint8_t *buf, size_t len) {
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bool sent = false;
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if (CONFIG_AFSK_TXWAIT > 0) {
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ticks_t wait_start = timer_clock();
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long wait_ticks = ms_to_ticks(CONFIG_AFSK_TXWAIT);
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while (timer_clock() - wait_start < wait_ticks) {
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cpu_relax();
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}
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}
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while (!sent) {
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if(!channel->hdlc.dcd) {
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uint8_t tp = rand() & 0xFF;
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if (tp < p) {
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ax25_sendRaw(ctx, buf, len);
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sent = true;
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} else {
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ticks_t start = timer_clock();
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long slot_ticks = ms_to_ticks(slotTime);
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while (timer_clock() - start < slot_ticks) {
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cpu_relax();
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}
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}
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} else {
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while (!sent && channel->hdlc.receiving) {
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// Continously poll the modem for data
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// while waiting, so we don't overrun
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// receive buffers
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ax25_poll(ax25ctx);
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if (channel->status != 0) {
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// If an overflow or other error
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// occurs, we'll back off and drop
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// this packet silently.
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channel->status = 0;
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sent = true;
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}
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}
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}
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}
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if (FLOWCONTROL) {
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while (!ctx->ready_for_data) { /* Wait */ }
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fputc(FEND, &serial->uart0);
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fputc(CMD_READY, &serial->uart0);
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fputc(0x01, &serial->uart0);
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fputc(FEND, &serial->uart0);
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}
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}
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void kiss_serialCallback(uint8_t sbyte) {
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if (IN_FRAME && sbyte == FEND && command == CMD_DATA) {
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IN_FRAME = false;
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kiss_csma(ax25ctx, serialBuffer, frame_len);
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} else if (sbyte == FEND) {
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IN_FRAME = true;
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command = CMD_UNKNOWN;
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frame_len = 0;
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} else if (IN_FRAME && frame_len < AX25_MAX_FRAME_LEN) {
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// Have a look at the command byte first
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if (frame_len == 0 && command == CMD_UNKNOWN) {
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// MicroModem supports only one HDLC port, so we
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// strip off the port nibble of the command byte
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sbyte = sbyte & 0x0F;
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command = sbyte;
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} else if (command == CMD_DATA) {
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if (sbyte == FESC) {
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ESCAPE = true;
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} else {
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if (ESCAPE) {
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if (sbyte == TFEND) sbyte = FEND;
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if (sbyte == TFESC) sbyte = FESC;
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ESCAPE = false;
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}
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serialBuffer[frame_len++] = sbyte;
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}
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} else if (command == CMD_TXDELAY) {
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custom_preamble = sbyte * 10UL;
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} else if (command == CMD_TXTAIL) {
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custom_tail = sbyte * 10;
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} else if (command == CMD_SLOTTIME) {
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slotTime = sbyte * 10;
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} else if (command == CMD_P) {
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p = sbyte;
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} else if (command == CMD_READY) {
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if (sbyte == 0x00) {
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FLOWCONTROL = false;
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} else {
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FLOWCONTROL = true;
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}
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}
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}
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} |