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