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/* Copyright 2018 Mike Roberts
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdbool.h>
#include "action.h"
#include <LUFA/Drivers/Peripheral/TWI.h>
#include <LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c>
#include "mcp23017.h"
#include "debug.h"
#include "wait.h"
uint8_t bit_for_pin(uint8_t pin);
uint8_t expander_write(uint8_t reg, uint8_t data);
uint8_t expander_read(uint8_t reg, uint8_t *data);
void expander_config(void);
static const char *twi_err_str(uint8_t res) {
switch (res) {
case TWI_ERROR_NoError:
return "OK";
case TWI_ERROR_BusFault:
return "BUSFAULT";
case TWI_ERROR_BusCaptureTimeout:
return "BUSTIMEOUT";
case TWI_ERROR_SlaveResponseTimeout:
return "SLAVETIMEOUT";
case TWI_ERROR_SlaveNotReady:
return "SLAVENOTREADY";
case TWI_ERROR_SlaveNAK:
return "SLAVENAK";
default:
return "UNKNOWN";
}
}
void expander_init(void) {
TWI_Init(TWI_BIT_PRESCALE_1, TWI_BITLENGTH_FROM_FREQ(1, 400000));
}
// set IN and HI
void expander_unselect_all(void) {
expander_write(EXPANDER_REG_IODIRA, 0xff);
expander_write(EXPANDER_REG_IODIRB, 0xff);
expander_write(EXPANDER_REG_OLATA, 0xff);
expander_write(EXPANDER_REG_OLATB, 0xff);
wait_us(EXPANDER_PAUSE);
}
// set OUT and LOW
void expander_select(uint8_t pin) {
const uint8_t mask = 0xff & ~(1 << bit_for_pin(pin));
if (pin < 8) {
expander_write(EXPANDER_REG_IODIRA, mask);
expander_write(EXPANDER_REG_OLATA, mask);
} else {
expander_write(EXPANDER_REG_IODIRB, mask);
expander_write(EXPANDER_REG_OLATB, mask);
}
wait_us(EXPANDER_PAUSE);
}
void expander_config(void) {
// set everything to input
expander_write(EXPANDER_REG_IODIRA, 0xff);
expander_write(EXPANDER_REG_IODIRB, 0xff);
// turn on pull-ups
expander_write(EXPANDER_REG_GPPUA, 0xff);
expander_write(EXPANDER_REG_GPPUB, 0xff);
// disable interrupts
expander_write(EXPANDER_REG_GPINTENA, 0x0);
expander_write(EXPANDER_REG_GPINTENB, 0x0);
// polarity
expander_write(EXPANDER_REG_IPOLA, 0x0);
expander_write(EXPANDER_REG_IPOLB, 0x0);
}
uint8_t bit_for_pin(uint8_t pin) {
return pin % 8;
}
uint8_t expander_write(uint8_t reg, unsigned char val) {
uint8_t addr = reg;
uint8_t result = TWI_WritePacket(EXPANDER_ADDR << 1, I2C_TIMEOUT, &addr, sizeof(addr), &val, sizeof(val));
if (result) {
xprintf("mcp: set_register %d = %d failed: %s\n", reg, val, twi_err_str(result));
}
return result == 0;
}
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