149 lines
3.7 KiB
C
149 lines
3.7 KiB
C
/* ---------------------------------------------------------------------------
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** This software is in the public domain, furnished "as is", without technical
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** support, and with no warranty, express or implied, as to its usefulness for
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** any purpose.
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**
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** ledmatrix.c
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**
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** Beschrijving: Simple HT16K33 Ledmatix demo.
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** Target: AVR mcu
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** Build: avr-gcc -std=c99 -Wall -O3 -mmcu=atmega128 -D F_CPU=8000000UL -c ledmatrix.c
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** avr-gcc -g -mmcu=atmega128 -o ledmatrix.elf ledmatrix.o
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** avr-objcopy -O ihex ledmatrix.elf ledmatrix.hex
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** or type 'make'
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** Author: dkroeske@gmail.com
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** -------------------------------------------------------------------------*/
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#include <avr/io.h>
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#include <util/delay.h>
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/******************************************************************/
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void twi_init(void)
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/*
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short: Init AVR TWI interface and set bitrate
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inputs:
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outputs:
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notes: TWI clock is set to 100 kHz
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Version : DMK, Initial code
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*******************************************************************/
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{
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TWSR = 0;
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TWBR = 32; // TWI clock set to 100kHz, prescaler = 0
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}
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/******************************************************************/
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void twi_start(void)
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/*
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short: Generate TWI start condition
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inputs:
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outputs:
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notes:
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Version : DMK, Initial code
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*******************************************************************/
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{
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TWCR = (0x80 | 0x20 | 0x04);
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while( 0x00 == (TWCR & 0x80) );
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}
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/******************************************************************/
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void twi_stop(void)
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/*
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short: Generate TWI stop condition
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inputs:
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outputs:
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notes:
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Version : DMK, Initial code
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*******************************************************************/
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{
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TWCR = (0x80 | 0x10 | 0x04);
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}
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/******************************************************************/
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void twi_tx(unsigned char data)
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/*
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short: transmit 8 bits data
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inputs:
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outputs:
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notes:
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Version : DMK, Initial code
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*******************************************************************/
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{
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TWDR = data;
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TWCR = (0x80 | 0x04);
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while( 0 == (TWCR & 0x80) );
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}
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/******************************************************************/
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void wait( int ms )
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/*
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short: Busy wait number of millisecs
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inputs: int ms (Number of millisecs to busy wait)
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outputs:
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notes: Busy wait, not very accurate. Make sure (external)
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clock value is set. This is used by _delay_ms inside
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util/delay.h
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Version : DMK, Initial code
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*******************************************************************/
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{
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for (int i=0; i<ms; i++)
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{
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_delay_ms( 1 ); // library function (max 30 ms at 8MHz)
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}
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}
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/******************************************************************/
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int main( void )
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/*
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short: main() loop, entry point of executable
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inputs:
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outputs:
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notes: Looping forever, trashing the HT16K33
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Version : DMK, Initial code
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*******************************************************************/
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{
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twi_init(); // Init TWI interface
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// Init HT16K22. Page 32 datasheet
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twi_start();
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twi_tx(0xE0); // Display I2C addres + R/W bit
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twi_tx(0x21); // Internal osc on (page 10 HT16K33)
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twi_stop();
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twi_start();
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twi_tx(0xE0); // Display I2C address + R/W bit
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twi_tx(0xA0); // HT16K33 pins all output
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twi_stop();
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twi_start();
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twi_tx(0xE0); // Display I2C address + R/W bit
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twi_tx(0xE3); // Display Dimming 4/16 duty cycle
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twi_stop();
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twi_start();
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twi_tx(0xE0); // Display I2C address + R/W bit
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twi_tx(0x81); // Display OFF - Blink On
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twi_stop();
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while (1)
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{
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twi_start();
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twi_tx(0xE0); // Display I2C addres + R/W bit
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twi_tx(0x00); // Address
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twi_tx(0x00); // data
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twi_stop();
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wait(500);
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twi_start();
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twi_tx(0xE0); // Display I2C addres + R/W bit
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twi_tx(0x00); // Address
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twi_tx(0x01); // data
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twi_stop();
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wait(500);
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}
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return 1;
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} |