131 lines
2.3 KiB
C
131 lines
2.3 KiB
C
#include <avr/io.h>
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#include <avr/interrupt.h>
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#include <avr/sleep.h>
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#include <tabby/printer.h>
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#include <tabby/avr/uart.h>
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#include <tabby/avr.h>
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static volatile tabby_printer_packet header;
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static volatile uint16_t i, b;
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/*
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* SPI byte receipt interrupt vector
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*/
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ISR(SPI_STC_vect) {
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uint8_t in = SPDR,
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out = 0;
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uart_putchar(in, NULL);
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switch (i) {
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case 0: {
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if (in == TABBY_PRINTER_SYNC_1) {
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header.preamble[0] = in;
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i++;
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b = 0;
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}
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break;
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}
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case 1: {
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if (in == TABBY_PRINTER_SYNC_2) {
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header.preamble[1] = in;
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i++;
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} else {
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i = 0;
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}
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break;
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}
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case 2: {
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header.type = in;
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i++;
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break;
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}
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case 3: {
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header.compression = in;
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i++;
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break;
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}
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case 4: {
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header.size = in;
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i++;
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break;
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}
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case 5: {
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header.size |= in << 8;
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i++;
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if (header.size > TABBY_PRINTER_PACKET_MAX_SIZE) {
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i = 0;
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}
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break;
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}
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default: {
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if (b <= header.size) {
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b++;
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} else if (b == header.size + 1) {
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b++;
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out = TABBY_PRINTER_DEVICE_ID;
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} else if (b == header.size + 2) {
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b++;
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out = TABBY_PRINTER_OK;
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} else if (b == header.size + 3) {
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i = 0;
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}
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}
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}
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SPDR = out;
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}
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static void spi_init() {
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SS_INPUT();
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SC_INPUT();
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SI_INPUT();
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SO_OUTPUT();
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/*
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* Set SPI slave mode, and shift in/out most significant bit first
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*/
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SPCR &= ~((1 << MSTR) | (1 << DORD));
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/*
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* Enable SPI in Mode 3 with interrupts, clock nominally high, output on
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* falling edge, input on rising edge
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*/
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SPCR |= (1 << CPOL) | (1 << CPHA) | (1 << SPIE) | (1 << SPE);
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/*
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* Initialize the SPI Data Register and serial buffer
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*/
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SPDR = 0;
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}
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int main() {
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uart_init();
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spi_init();
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sei();
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while (1) {
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sleep_mode();
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}
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return 0;
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}
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