jens
d2a116ce13
git-svn-id: http://moon:8086/svn/projects/HendiControl@161 fda53097-d464-4ada-af97-ba876c37ca34
77 lines
1.8 KiB
C
77 lines
1.8 KiB
C
/*
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* i2c.c
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*
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* Created: 20.02.2019 20:33:30
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* Author: jens
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*/
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#include <stdio.h>
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#include <avr/io.h>
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#include "i2c.h"
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void i2c_init()
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{
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TWBR = 0xFF;
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TWSR = 0x00;
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}
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void i2c_send(uint8_t addr, uint8_t rw, uint8_t *data, size_t size)
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{
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TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN);
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// Send START condition
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do
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{
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while (!(TWCR &(1<<TWINT))); // Wait for TWINT Flag set. This indicates
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// that the START condition has been
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// transmitted.
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if((TWSR & 0xF8) != I2C_START)
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{
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printf("Error I2C_START\n");
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break;
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}
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TWDR = addr<<1 | rw; // Load SLA_W into TWDR Register. Clear
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// TWINT bit in TWCR to start transmission of
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// address.
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TWCR = (1<<TWINT) | (1<<TWEN);
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while (!(TWCR &(1<<TWINT))); // Wait for TWINT Flag set. This indicates
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// that the SLA+W has been transmitted, and
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// ACK/NACK has been received.
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if ((TWSR & 0xF8) != I2C_SLA_ACK)
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{
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printf("Error I2C_SLA_ACK\n");
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break;
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}
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// Check value of TWI Status Register. Mask
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// prescaler bits. If status different from
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// MT_SLA_ACK go to ERROR
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for (size_t i=0; i < size; i++)
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{
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TWDR = *(data++);
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TWCR = (1<<TWINT) | (1<<TWEN);
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// Load DATA into TWDR Register. Clear
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// TWINT bit in TWCR to start transmission of
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// data.
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while (!(TWCR & (1<<TWINT)));
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// Wait for TWINT Flag set. This indicates
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// that the DATA has been transmitted, and
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// ACK/NACK has been received}
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if ((TWSR & 0xF8) != I2C_DATA_ACK)
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{
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printf("Error I2C_DATA_ACK\n");
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break;
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}
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// Check value of TWI Status Register. Mask
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// prescaler bits. If status different from
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// MT_DATA_ACK go to ERROR.
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}
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} while (0);
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TWCR = (1<<TWINT)| (1<<TWEN)|(1<<TWSTO); // Transmit STOP condition.
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}
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