134 lines
3.1 KiB
C
134 lines
3.1 KiB
C
/* ----------------------------------------------------------------------------
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* ergoDOX controller: MCP23018 specific code
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* ----------------------------------------------------------------------------
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* Copyright (c) 2012 Ben Blazak <benblazak.dev@gmail.com>
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* Released under The MIT License (MIT) (see "license.md")
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* Project located at <https://github.com/benblazak/ergodox-firmware>
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* ------------------------------------------------------------------------- */
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#include <util/twi.h>
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#include "lib/data-types.h"
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#define TWI_FREQ 400000
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#include "lib/teensy-2-0/twi.h"
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#include "matrix.h"
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#define MCP23018_h_INCLUDE_PRIVATE
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#include "mcp23018.h"
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// register addresses (see "mcp23018.md")
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#define IODIRA 0x00 // i/o direction register
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#define IODIRB 0x01
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#define GPPUA 0x0C // GPIO pull-up resistor register
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#define GPPUB 0x0D
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#define GPIOA 0x12 // general purpose i/o port register
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#define GPIOB 0x13
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#define OLATA 0x14 // output latch register
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#define OLATB 0x15
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// TWI aliases
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#define TWI_ADDR_WRITE ( (MCP23018_TWI_ADDRESS<<1) | TW_WRITE )
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#define TWI_ADDR_READ ( (MCP23018_TWI_ADDRESS<<1) | TW_READ )
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// error check
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#if KB_ROWS != 12 || KB_COLUMNS != 7
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#error "Expecting different keyboard dimensions"
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#endif
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/*
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* returns:
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* - success: 0
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* - failure: twi status code
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*/
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uint8_t mcp23018_init(void) {
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uint8_t ret;
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twi_init();
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// quick check to see if the device is responding; if it is, we'll
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// assume things are going to work
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twi_start();
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ret = twi_send(TWI_ADDR_WRITE);
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if (ret) {
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twi_stop();
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return ret;
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}
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// set pin direction
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// - unused : input : 1
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// - rows : output : 0
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// - columns : input : 1
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twi_start();
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twi_send(TWI_ADDR_WRITE);
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twi_send(IODIRA);
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twi_send(0b11000000); // IODIRA
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twi_send(0b11111111); // IODIRB
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// set pull-up
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// - unused : on : 1
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// - rows : on : 1
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// - columns : on : 1
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twi_start();
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twi_send(TWI_ADDR_WRITE);
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twi_send(GPPUA);
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twi_send(0b11111111); // GPPUA
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twi_send(0b11111111); // GPPUB
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// set output pins high
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// - unused : low : 0
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// - rows : high : 1
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// - columns : low : 0
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twi_start();
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twi_send(TWI_ADDR_WRITE);
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twi_send(GPIOA);
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twi_send(0b00111111); //GPIOA
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twi_send(0b00000000); //GPIOB
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twi_stop();
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}
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/* args:
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* - `matrix[][]`: `KB_ROWS` and `KB_COLUMNS` must be what we're expecting (see
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* 'error check' in the `#include` section)
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*
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* returns:
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* - success: 0
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* - failure: twi status code
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*/
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uint8_t mcp23018_update_matrix(uint8_t matrix[KB_ROWS][KB_COLUMNS]) {
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uint8_t ret, data;
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// quick check to see if the device is responding; if it is, we'll
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// assume things are going to work
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twi_start();
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ret = twi_send(TWI_ADDR_WRITE);
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if (ret) {
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twi_stop();
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return ret;
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}
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for (uint8_t row=0x6; row<=0xB; row++) {
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// set row low : 0
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twi_start();
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twi_send(TWI_ADDR_WRITE);
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twi_send(GPIOA);
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twi_send( 0b00111111 & ~(1<<(row-6)) ); // GPIOA
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// get column data
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twi_start();
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twi_send(TWI_ADDR_READ);
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twi_read(&data); // GPIOB TODO: confirm
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// update matrix
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for (uint8_t col=0; col<=6; col++)
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matrix[row][col] = !( data & (1<<col) );
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}
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twi_stop();
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}
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