98 lines
2.9 KiB
C
98 lines
2.9 KiB
C
/*
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* Code to write data to TPIC6B595 SIPO shift register.
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*
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* The TPIC6B595 is a monolithic, high-voltage, medium-current power 8-bit
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* shift register designed for use in systems that require relatively high
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* load power.
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*
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* This device contains an 8-bit serial-in, parallel-out shift register that
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* feeds an 8-bit D-type storage register. Data transfers through both the
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* shift and storage registers on the rising edge of the shift-register clock
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* (SRCK) and the register clock (RCK), respectively. The storage register
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* transfers data to the output buffer when shift-register clear (SRCLR) is
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* high. When SRCLR is low, the input shift register is cleared. When output
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* enable (G) is held high, all data in the output buffers is held low and all
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* drain outputs are off. When G is held low, data from the storage register
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* is transparent to the output buffers. When data in the output buffers is
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* low, the DMOS-transistor outputs are off. When data is high, the DMOS-
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* transistor outputs have sink-current capability. The serial output (SER
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* OUT) allows for cascading of the data from the shift register to additional
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* devices.
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*
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* http://www.adafruit.com/datasheets/tpic6b595.pdf
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*
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* To compile and upload run: make clean; make; make program;
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*
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* Copyright 2011 Mika Tuupola
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*
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* Licensed under the MIT license:
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* http://www.opensource.org/licenses/mit-license.php
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*
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <util/delay.h>
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#include "main.h"
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#include "uart.h"
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#include "pins.h"
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#include "digital.h"
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#define LATCH 8 /* RCK */
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#define CLOCK 12 /* SRCK */
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#define DATA 11 /* SER IN */
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static void init(void) {
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pin_mode(LATCH, OUTPUT);
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pin_mode(CLOCK, OUTPUT);
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pin_mode(DATA, OUTPUT);
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}
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/* Assumes MSB first. */
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void shift_out(uint8_t data) {
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for(uint8_t i = 0; i < 8; i++) {
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/* Write bit to data port. */
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if (0 == (data & _BV(7 - i))) {
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digital_write(DATA, LOW);
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} else {
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digital_write(DATA, HIGH);
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}
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/* Pulse clock input to write next bit. */
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digital_write(CLOCK, LOW);
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digital_write(CLOCK, HIGH);
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}
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}
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int main(void) {
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init();
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uart_init();
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stdout = &uart_output;
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stdin = &uart_input;
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uint8_t binary[9];
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while (1) {
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for(uint8_t i = 0; i < 256; i++) {
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/* Print the number to serial for debugging. */
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itoa(i, binary, 2);
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printf("%s %d \n", binary, i);
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/* Shift current number to shift register. */
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shift_out(i);
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/* Pulse latch to transfer data from shift registers */
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/* to storage registers (should this be inside shift_out()?). */
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digital_write(LATCH, LOW);
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digital_write(LATCH, HIGH);
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_delay_ms(250);
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}
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}
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return 0;
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}
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