~ruther/qmk_firmware

3d06860f3cd8af5d9a2b4e9736b3024d0f37343f — Joel Challis 3 years ago 3716e02
Convert not_so_minidox to SPLIT_KEYBOARD (#15306)

10 files changed, 21 insertions(+), 929 deletions(-)

M keyboards/handwired/not_so_minidox/config.h
D keyboards/handwired/not_so_minidox/i2c.c
D keyboards/handwired/not_so_minidox/i2c.h
M keyboards/handwired/not_so_minidox/keymaps/default/keymap.c
D keyboards/handwired/not_so_minidox/matrix.c
M keyboards/handwired/not_so_minidox/rules.mk
D keyboards/handwired/not_so_minidox/serial.c
D keyboards/handwired/not_so_minidox/serial.h
D keyboards/handwired/not_so_minidox/split_util.c
D keyboards/handwired/not_so_minidox/split_util.h
M keyboards/handwired/not_so_minidox/config.h => keyboards/handwired/not_so_minidox/config.h +5 -0
@@ 40,6 40,11 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.

#define USE_SERIAL

/*
 * Split Keyboard specific options, make sure you have 'SPLIT_KEYBOARD = yes' in your rules.mk, and define SOFT_SERIAL_PIN.
 */
#define SOFT_SERIAL_PIN D0  // or D1, D2, D3, E6

//#define EE_HANDS

#define MASTER_LEFT

D keyboards/handwired/not_so_minidox/i2c.c => keyboards/handwired/not_so_minidox/i2c.c +0 -162
@@ 1,162 0,0 @@
#include <util/twi.h>
#include <avr/io.h>
#include <stdlib.h>
#include <avr/interrupt.h>
#include <util/twi.h>
#include <stdbool.h>
#include "i2c.h"

#ifdef USE_I2C

// Limits the amount of we wait for any one i2c transaction.
// Since were running SCL line 100kHz (=> 10μs/bit), and each transactions is
// 9 bits, a single transaction will take around 90μs to complete.
//
// (F_CPU/SCL_CLOCK)  =>  # of μC cycles to transfer a bit
// poll loop takes at least 8 clock cycles to execute
#define I2C_LOOP_TIMEOUT (9+1)*(F_CPU/SCL_CLOCK)/8

#define BUFFER_POS_INC() (slave_buffer_pos = (slave_buffer_pos+1)%SLAVE_BUFFER_SIZE)

volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE];

static volatile uint8_t slave_buffer_pos;
static volatile bool slave_has_register_set = false;

// Wait for an i2c operation to finish
inline static
void i2c_delay(void) {
  uint16_t lim = 0;
  while(!(TWCR & (1<<TWINT)) && lim < I2C_LOOP_TIMEOUT)
    lim++;

  // easier way, but will wait slightly longer
  // _delay_us(100);
}

// Setup twi to run at 100kHz
void i2c_master_init(void) {
  // no prescaler
  TWSR = 0;
  // Set TWI clock frequency to SCL_CLOCK. Need TWBR>10.
  // Check datasheets for more info.
  TWBR = ((F_CPU/SCL_CLOCK)-16)/2;
}

// Start a transaction with the given i2c slave address. The direction of the
// transfer is set with I2C_READ and I2C_WRITE.
// returns: 0 => success
//          1 => error
uint8_t i2c_master_start(uint8_t address) {
  TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTA);

  i2c_delay();

  // check that we started successfully
  if ( (TW_STATUS != TW_START) && (TW_STATUS != TW_REP_START))
    return 1;

  TWDR = address;
  TWCR = (1<<TWINT) | (1<<TWEN);

  i2c_delay();

  if ( (TW_STATUS != TW_MT_SLA_ACK) && (TW_STATUS != TW_MR_SLA_ACK) )
    return 1; // slave did not acknowledge
  else
    return 0; // success
}


// Finish the i2c transaction.
void i2c_master_stop(void) {
  TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);

  uint16_t lim = 0;
  while(!(TWCR & (1<<TWSTO)) && lim < I2C_LOOP_TIMEOUT)
    lim++;
}

// Write one byte to the i2c slave.
// returns 0 => slave ACK
//         1 => slave NACK
uint8_t i2c_master_write(uint8_t data) {
  TWDR = data;
  TWCR = (1<<TWINT) | (1<<TWEN);

  i2c_delay();

  // check if the slave acknowledged us
  return (TW_STATUS == TW_MT_DATA_ACK) ? 0 : 1;
}

// Read one byte from the i2c slave. If ack=1 the slave is acknowledged,
// if ack=0 the acknowledge bit is not set.
// returns: byte read from i2c device
uint8_t i2c_master_read(int ack) {
  TWCR = (1<<TWINT) | (1<<TWEN) | (ack<<TWEA);

  i2c_delay();
  return TWDR;
}

void i2c_reset_state(void) {
  TWCR = 0;
}

void i2c_slave_init(uint8_t address) {
  TWAR = address << 0; // slave i2c address
  // TWEN  - twi enable
  // TWEA  - enable address acknowledgement
  // TWINT - twi interrupt flag
  // TWIE  - enable the twi interrupt
  TWCR = (1<<TWIE) | (1<<TWEA) | (1<<TWINT) | (1<<TWEN);
}

ISR(TWI_vect);

ISR(TWI_vect) {
  uint8_t ack = 1;
  switch(TW_STATUS) {
    case TW_SR_SLA_ACK:
      // this device has been addressed as a slave receiver
      slave_has_register_set = false;
      break;

    case TW_SR_DATA_ACK:
      // this device has received data as a slave receiver
      // The first byte that we receive in this transaction sets the location
      // of the read/write location of the slaves memory that it exposes over
      // i2c.  After that, bytes will be written at slave_buffer_pos, incrementing
      // slave_buffer_pos after each write.
      if(!slave_has_register_set) {
        slave_buffer_pos = TWDR;
        // don't acknowledge the master if this memory loctaion is out of bounds
        if ( slave_buffer_pos >= SLAVE_BUFFER_SIZE ) {
          ack = 0;
          slave_buffer_pos = 0;
        }
        slave_has_register_set = true;
      } else {
        i2c_slave_buffer[slave_buffer_pos] = TWDR;
        BUFFER_POS_INC();
      }
      break;

    case TW_ST_SLA_ACK:
    case TW_ST_DATA_ACK:
      // master has addressed this device as a slave transmitter and is
      // requesting data.
      TWDR = i2c_slave_buffer[slave_buffer_pos];
      BUFFER_POS_INC();
      break;

    case TW_BUS_ERROR: // something went wrong, reset twi state
      TWCR = 0;
    default:
      break;
  }
  // Reset everything, so we are ready for the next TWI interrupt
  TWCR |= (1<<TWIE) | (1<<TWINT) | (ack<<TWEA) | (1<<TWEN);
}
#endif

D keyboards/handwired/not_so_minidox/i2c.h => keyboards/handwired/not_so_minidox/i2c.h +0 -46
@@ 1,46 0,0 @@
#pragma once

#include <stdint.h>

#ifndef F_CPU
#define F_CPU 16000000UL
#endif

#define I2C_READ 1
#define I2C_WRITE 0

#define I2C_ACK 1
#define I2C_NACK 0

#define SLAVE_BUFFER_SIZE 0x10

// i2c SCL clock frequency
#define SCL_CLOCK  400000L

extern volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE];

void i2c_master_init(void);
uint8_t i2c_master_start(uint8_t address);
void i2c_master_stop(void);
uint8_t i2c_master_write(uint8_t data);
uint8_t i2c_master_read(int);
void i2c_reset_state(void);
void i2c_slave_init(uint8_t address);


static inline unsigned char i2c_start_read(unsigned char addr) {
  return i2c_master_start((addr << 1) | I2C_READ);
}

static inline unsigned char i2c_start_write(unsigned char addr) {
  return i2c_master_start((addr << 1) | I2C_WRITE);
}

// from SSD1306 scrips
extern unsigned char i2c_rep_start(unsigned char addr);
extern void i2c_start_wait(unsigned char addr);
extern unsigned char i2c_readAck(void);
extern unsigned char i2c_readNak(void);
extern unsigned char i2c_read(unsigned char ack);

#define i2c_read(ack)  (ack) ? i2c_readAck() : i2c_readNak();

M keyboards/handwired/not_so_minidox/keymaps/default/keymap.c => keyboards/handwired/not_so_minidox/keymaps/default/keymap.c +5 -51
@@ 8,17 8,10 @@
#define _QWERTY 0
#define _LOWER 1
#define _RAISE 2
#define _ADJUST 16
#define _ADJUST 3

enum custom_keycodes {
  QWERTY = SAFE_RANGE,
  LOWER,
  RAISE,
  ADJUST,
};

#define KC_LOWR LOWER
#define KC_RASE RAISE
#define KC_LOWR MO(_LOWER)
#define KC_RASE MO(_RAISE)
#define KC_RST  RESET
#define KC_CAD  LCTL(LALT(KC_DEL))



@@ 72,45 65,6 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
  )
};


bool process_record_user(uint16_t keycode, keyrecord_t *record) {
  switch (keycode) {
    case QWERTY:
      if (record->event.pressed) {
        set_single_persistent_default_layer(_QWERTY);
      }
      return false;
      break;
    case LOWER:
      if (record->event.pressed) {
        layer_on(_LOWER);
        update_tri_layer(_LOWER, _RAISE, _ADJUST);
      } else {
        layer_off(_LOWER);
        update_tri_layer(_LOWER, _RAISE, _ADJUST);
      }
      return false;
      break;
    case RAISE:
      if (record->event.pressed) {
        layer_on(_RAISE);
        update_tri_layer(_LOWER, _RAISE, _ADJUST);
      } else {
        layer_off(_RAISE);
        update_tri_layer(_LOWER, _RAISE, _ADJUST);
      }
      return false;
      break;
    case ADJUST:
      if (record->event.pressed) {
        layer_on(_ADJUST);
        update_tri_layer(_LOWER, _RAISE, _ADJUST);
      } else {
        layer_off(_ADJUST);
        update_tri_layer(_LOWER, _RAISE, _ADJUST);
      }
      return false;
      break;
  }
  return true;
layer_state_t layer_state_set_user(layer_state_t state) {
  return update_tri_layer_state(state, _RAISE, _LOWER, _ADJUST);
}

D keyboards/handwired/not_so_minidox/matrix.c => keyboards/handwired/not_so_minidox/matrix.c +0 -302
@@ 1,302 0,0 @@
/*
Copyright 2012 Jun Wako <wakojun@gmail.com>

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/>.
*/

/*
 * scan matrix
 */
#include <stdint.h>
#include <stdbool.h>
#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include "print.h"
#include "debug.h"
#include "util.h"
#include "matrix.h"
#include "split_util.h"
#include "config.h"
#include "quantum.h"

#ifdef USE_I2C
#  include "i2c.h"
#else // USE_SERIAL
#  include "serial.h"
#endif

#ifndef DEBOUNCE
#  define DEBOUNCE	5
#endif

#define ERROR_DISCONNECT_COUNT 5

static uint8_t debouncing = DEBOUNCE;
static const int ROWS_PER_HAND = MATRIX_ROWS/2;
static uint8_t error_count = 0;

static const uint8_t row_pins[MATRIX_ROWS] = MATRIX_ROW_PINS;
static const uint8_t col_pins[MATRIX_COLS] = MATRIX_COL_PINS;

/* matrix state(1:on, 0:off) */
static matrix_row_t matrix[MATRIX_ROWS];
static matrix_row_t matrix_debouncing[MATRIX_ROWS];

static matrix_row_t read_cols(void);
static void init_cols(void);
static void unselect_rows(void);
static void select_row(uint8_t row);


__attribute__ ((weak))
void matrix_init_kb(void) {
    matrix_init_user();
}

__attribute__ ((weak))
void matrix_scan_kb(void) {
    matrix_scan_user();
}

__attribute__ ((weak))
void matrix_init_user(void) {
}

__attribute__ ((weak))
void matrix_scan_user(void) {
}

inline
uint8_t matrix_rows(void)
{
    return MATRIX_ROWS;
}

inline
uint8_t matrix_cols(void)
{
    return MATRIX_COLS;
}

void matrix_init(void)
{
    debug_enable = true;
    debug_matrix = true;
    debug_mouse = true;
    // initialize row and col
    unselect_rows();
    init_cols();

    setPinOutput(B0);
    setPinOutput(D5);

    // initialize matrix state: all keys off
    for (uint8_t i=0; i < MATRIX_ROWS; i++) {
        matrix[i] = 0;
        matrix_debouncing[i] = 0;
    }

    matrix_init_quantum();
}

uint8_t _matrix_scan(void)
{
    // Right hand is stored after the left in the matirx so, we need to offset it
    int offset = isLeftHand ? 0 : (ROWS_PER_HAND);

    for (uint8_t i = 0; i < ROWS_PER_HAND; i++) {
        select_row(i);
        _delay_us(30);  // without this wait read unstable value.
        matrix_row_t cols = read_cols();
        if (matrix_debouncing[i+offset] != cols) {
            matrix_debouncing[i+offset] = cols;
            debouncing = DEBOUNCE;
        }
        unselect_rows();
    }

    if (debouncing) {
        if (--debouncing) {
            _delay_ms(1);
        } else {
            for (uint8_t i = 0; i < ROWS_PER_HAND; i++) {
                matrix[i+offset] = matrix_debouncing[i+offset];
            }
        }
    }

    return 1;
}

#ifdef USE_I2C

// Get rows from other half over i2c
int i2c_transaction(void) {
    int slaveOffset = (isLeftHand) ? (ROWS_PER_HAND) : 0;

    int err = i2c_master_start(SLAVE_I2C_ADDRESS + I2C_WRITE);
    if (err) goto i2c_error;

    // start of matrix stored at 0x00
    err = i2c_master_write(0x00);
    if (err) goto i2c_error;

    // Start read
    err = i2c_master_start(SLAVE_I2C_ADDRESS + I2C_READ);
    if (err) goto i2c_error;

    if (!err) {
        int i;
        for (i = 0; i < ROWS_PER_HAND-1; ++i) {
            matrix[slaveOffset+i] = i2c_master_read(I2C_ACK);
        }
        matrix[slaveOffset+i] = i2c_master_read(I2C_NACK);
        i2c_master_stop();
    } else {
i2c_error: // the cable is disconnceted, or something else went wrong
        i2c_reset_state();
        return err;
    }

    return 0;
}

#else // USE_SERIAL

int serial_transaction(void) {
    int slaveOffset = (isLeftHand) ? (ROWS_PER_HAND) : 0;

    if (serial_update_buffers()) {
        return 1;
    }

    for (int i = 0; i < ROWS_PER_HAND; ++i) {
        matrix[slaveOffset+i] = serial_slave_buffer[i];
    }
    return 0;
}
#endif

uint8_t matrix_scan(void)
{
    int ret = _matrix_scan();



#ifdef USE_I2C
    if( i2c_transaction() ) {
#else // USE_SERIAL
    if( serial_transaction() ) {
#endif
        // turn on the indicator led when halves are disconnected
        writePinLow(D5);

        error_count++;

        if (error_count > ERROR_DISCONNECT_COUNT) {
            // reset other half if disconnected
            int slaveOffset = (isLeftHand) ? (ROWS_PER_HAND) : 0;
            for (int i = 0; i < ROWS_PER_HAND; ++i) {
                matrix[slaveOffset+i] = 0;
            }
        }
    } else {
        // turn off the indicator led on no error
        writePinHigh(D5);
        error_count = 0;
    }
    matrix_scan_quantum();
    return ret;
}

void matrix_slave_scan(void) {
    _matrix_scan();

    int offset = (isLeftHand) ? 0 : (MATRIX_ROWS / 2);

#ifdef USE_I2C
    for (int i = 0; i < ROWS_PER_HAND; ++i) {
        /* i2c_slave_buffer[i] = matrix[offset+i]; */
        i2c_slave_buffer[i] = matrix[offset+i];
    }
#else // USE_SERIAL
    for (int i = 0; i < ROWS_PER_HAND; ++i) {
        serial_slave_buffer[i] = matrix[offset+i];
    }
#endif
}

inline
bool matrix_is_on(uint8_t row, uint8_t col)
{
    return (matrix[row] & ((matrix_row_t)1<<col));
}

inline
matrix_row_t matrix_get_row(uint8_t row)
{
    return matrix[row];
}

void matrix_print(void)
{
    print("\nr/c 0123456789ABCDEF\n");
    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
        print_hex8(row); print(": ");
        print_bin_reverse16(matrix_get_row(row));
        print("\n");
    }
}

uint8_t matrix_key_count(void)
{
    uint8_t count = 0;
    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
        count += bitpop16(matrix[i]);
    }
    return count;
}

static void  init_cols(void)
{
    for(int x = 0; x < MATRIX_COLS; x++) {
        _SFR_IO8((col_pins[x] >> 4) + 1) &=  ~_BV(col_pins[x] & 0xF);
        _SFR_IO8((col_pins[x] >> 4) + 2) |= _BV(col_pins[x] & 0xF);
    }
}

static matrix_row_t read_cols(void)
{
    matrix_row_t result = 0;
    for(int x = 0; x < MATRIX_COLS; x++) {
        result |= (_SFR_IO8(col_pins[x] >> 4) & _BV(col_pins[x] & 0xF)) ? 0 : (1 << x);
    }
    return result;
}

static void unselect_rows(void)
{
    for(int x = 0; x < ROWS_PER_HAND; x++) {
        _SFR_IO8((row_pins[x] >> 4) + 1) &=  ~_BV(row_pins[x] & 0xF);
        _SFR_IO8((row_pins[x] >> 4) + 2) |= _BV(row_pins[x] & 0xF);
    }
}

static void select_row(uint8_t row)
{
    _SFR_IO8((row_pins[row] >> 4) + 1) |=  _BV(row_pins[row] & 0xF);
    _SFR_IO8((row_pins[row] >> 4) + 2) &= ~_BV(row_pins[row] & 0xF);
}

M keyboards/handwired/not_so_minidox/rules.mk => keyboards/handwired/not_so_minidox/rules.mk +11 -16
@@ 5,24 5,19 @@ MCU = atmega32u4
BOOTLOADER = caterina

# Build Options
#   change to "no" to disable the options, or define them in the Makefile in
#   the appropriate keymap folder that will get included automatically
#   change yes to no to disable
#
BOOTMAGIC_ENABLE = no       # Enable Bootmagic Lite
BOOTMAGIC_ENABLE = yes      # Enable Bootmagic Lite
MOUSEKEY_ENABLE = yes       # Mouse keys
EXTRAKEY_ENABLE = no       # Audio control and System control
EXTRAKEY_ENABLE = yes       # Audio control and System control
CONSOLE_ENABLE = no         # Console for debug
COMMAND_ENABLE = yes        # Commands for debug and configuration
NKRO_ENABLE = no            # Nkey Rollover - if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
BACKLIGHT_ENABLE = no      # Enable keyboard backlight functionality
AUDIO_ENABLE = no           # Audio output
RGBLIGHT_ENABLE = no       # Enable WS2812 RGB underlight. 
USE_I2C = no
COMMAND_ENABLE = no         # Commands for debug and configuration
# Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
# if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
NKRO_ENABLE = no            # USB Nkey Rollover
BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
RGBLIGHT_ENABLE = no        # Enable keyboard RGB underglow
AUDIO_ENABLE = no           # Audio output

CUSTOM_MATRIX = yes
SRC += matrix.c \
	   i2c.c \
	   split_util.c \
	   serial.c
SPLIT_KEYBOARD = yes

D keyboards/handwired/not_so_minidox/serial.c => keyboards/handwired/not_so_minidox/serial.c +0 -228
@@ 1,228 0,0 @@
/*
 * WARNING: be careful changing this code, it is very timing dependent
 */

#ifndef F_CPU
#define F_CPU 16000000
#endif

#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <stdbool.h>
#include "serial.h"

#ifndef USE_I2C

// Serial pulse period in microseconds. Its probably a bad idea to lower this
// value.
#define SERIAL_DELAY 24

uint8_t volatile serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH] = {0};
uint8_t volatile serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH] = {0};

#define SLAVE_DATA_CORRUPT (1<<0)
volatile uint8_t status = 0;

inline static
void serial_delay(void) {
  _delay_us(SERIAL_DELAY);
}

inline static
void serial_output(void) {
  SERIAL_PIN_DDR |= SERIAL_PIN_MASK;
}

// make the serial pin an input with pull-up resistor
inline static
void serial_input(void) {
  SERIAL_PIN_DDR  &= ~SERIAL_PIN_MASK;
  SERIAL_PIN_PORT |= SERIAL_PIN_MASK;
}

inline static
uint8_t serial_read_pin(void) {
  return !!(SERIAL_PIN_INPUT & SERIAL_PIN_MASK);
}

inline static
void serial_low(void) {
  SERIAL_PIN_PORT &= ~SERIAL_PIN_MASK;
}

inline static
void serial_high(void) {
  SERIAL_PIN_PORT |= SERIAL_PIN_MASK;
}

void serial_master_init(void) {
  serial_output();
  serial_high();
}

void serial_slave_init(void) {
  serial_input();

  // Enable INT0
  EIMSK |= _BV(INT0);
  // Trigger on falling edge of INT0
  EICRA &= ~(_BV(ISC00) | _BV(ISC01));
}

// Used by the master to synchronize timing with the slave.
static
void sync_recv(void) {
  serial_input();
  // This shouldn't hang if the slave disconnects because the
  // serial line will float to high if the slave does disconnect.
  while (!serial_read_pin());
  serial_delay();
}

// Used by the slave to send a synchronization signal to the master.
static
void sync_send(void) {
  serial_output();

  serial_low();
  serial_delay();

  serial_high();
}

// Reads a byte from the serial line
static
uint8_t serial_read_byte(void) {
  uint8_t byte = 0;
  serial_input();
  for ( uint8_t i = 0; i < 8; ++i) {
    byte = (byte << 1) | serial_read_pin();
    serial_delay();
    _delay_us(1);
  }

  return byte;
}

// Sends a byte with MSB ordering
static
void serial_write_byte(uint8_t data) {
  uint8_t b = 8;
  serial_output();
  while( b-- ) {
    if(data & (1 << b)) {
      serial_high();
    } else {
      serial_low();
    }
    serial_delay();
  }
}

// interrupt handle to be used by the slave device
ISR(SERIAL_PIN_INTERRUPT) {
  sync_send();

  uint8_t checksum = 0;
  for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) {
    serial_write_byte(serial_slave_buffer[i]);
    sync_send();
    checksum += serial_slave_buffer[i];
  }
  serial_write_byte(checksum);
  sync_send();

  // wait for the sync to finish sending
  serial_delay();

  // read the middle of pulses
  _delay_us(SERIAL_DELAY/2);

  uint8_t checksum_computed = 0;
  for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) {
    serial_master_buffer[i] = serial_read_byte();
    sync_send();
    checksum_computed += serial_master_buffer[i];
  }
  uint8_t checksum_received = serial_read_byte();
  sync_send();

  serial_input(); // end transaction

  if ( checksum_computed != checksum_received ) {
    status |= SLAVE_DATA_CORRUPT;
  } else {
    status &= ~SLAVE_DATA_CORRUPT;
  }
}

inline
bool serial_slave_DATA_CORRUPT(void) {
  return status & SLAVE_DATA_CORRUPT;
}

// Copies the serial_slave_buffer to the master and sends the
// serial_master_buffer to the slave.
//
// Returns:
// 0 => no error
// 1 => slave did not respond
int serial_update_buffers(void) {
  // this code is very time dependent, so we need to disable interrupts
  cli();

  // signal to the slave that we want to start a transaction
  serial_output();
  serial_low();
  _delay_us(1);

  // wait for the slaves response
  serial_input();
  serial_high();
  _delay_us(SERIAL_DELAY);

  // check if the slave is present
  if (serial_read_pin()) {
    // slave failed to pull the line low, assume not present
    sei();
    return 1;
  }

  // if the slave is present syncronize with it
  sync_recv();

  uint8_t checksum_computed = 0;
  // receive data from the slave
  for (int i = 0; i < SERIAL_SLAVE_BUFFER_LENGTH; ++i) {
    serial_slave_buffer[i] = serial_read_byte();
    sync_recv();
    checksum_computed += serial_slave_buffer[i];
  }
  uint8_t checksum_received = serial_read_byte();
  sync_recv();

  if (checksum_computed != checksum_received) {
    sei();
    return 1;
  }

  uint8_t checksum = 0;
  // send data to the slave
  for (int i = 0; i < SERIAL_MASTER_BUFFER_LENGTH; ++i) {
    serial_write_byte(serial_master_buffer[i]);
    sync_recv();
    checksum += serial_master_buffer[i];
  }
  serial_write_byte(checksum);
  sync_recv();

  // always, release the line when not in use
  serial_output();
  serial_high();

  sei();
  return 0;
}

#endif

D keyboards/handwired/not_so_minidox/serial.h => keyboards/handwired/not_so_minidox/serial.h +0 -23
@@ 1,23 0,0 @@
#pragma once

#include "config.h"
#include <stdbool.h>

/* TODO:  some defines for interrupt setup */
#define SERIAL_PIN_DDR DDRD
#define SERIAL_PIN_PORT PORTD
#define SERIAL_PIN_INPUT PIND
#define SERIAL_PIN_MASK _BV(PD0)
#define SERIAL_PIN_INTERRUPT INT0_vect

#define SERIAL_SLAVE_BUFFER_LENGTH MATRIX_ROWS/2
#define SERIAL_MASTER_BUFFER_LENGTH 1

// Buffers for master - slave communication
extern volatile uint8_t serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH];
extern volatile uint8_t serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH];

void serial_master_init(void);
void serial_slave_init(void);
int serial_update_buffers(void);
bool serial_slave_data_corrupt(void);

D keyboards/handwired/not_so_minidox/split_util.c => keyboards/handwired/not_so_minidox/split_util.c +0 -84
@@ 1,84 0,0 @@
#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/power.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <avr/eeprom.h>
#include "split_util.h"
#include "matrix.h"
#include "keyboard.h"
#include "config.h"

#ifdef USE_I2C
#  include "i2c.h"
#else
#  include "serial.h"
#endif

volatile bool isLeftHand = true;

static void setup_handedness(void) {
  #ifdef EE_HANDS
    isLeftHand = eeprom_read_byte(EECONFIG_HANDEDNESS);
  #else
    // I2C_MASTER_RIGHT is deprecated, use MASTER_RIGHT instead, since this works for both serial and i2c
    #if defined(I2C_MASTER_RIGHT) || defined(MASTER_RIGHT)
      isLeftHand = !has_usb();
    #else
      isLeftHand = has_usb();
    #endif
  #endif
}

static void keyboard_master_setup(void) {
#ifdef USE_I2C
    i2c_master_init();
#ifdef SSD1306OLED
    matrix_master_OLED_init ();
#endif
#else
    serial_master_init();
#endif
}

static void keyboard_slave_setup(void) {
#ifdef USE_I2C
    i2c_slave_init(SLAVE_I2C_ADDRESS);
#else
    serial_slave_init();
#endif
}

bool has_usb(void) {
   USBCON |= (1 << OTGPADE); //enables VBUS pad
   _delay_us(5);
   return (USBSTA & (1<<VBUS));  //checks state of VBUS
}

void split_keyboard_setup(void) {
   setup_handedness();

   if (has_usb()) {
      keyboard_master_setup();
   } else {
      keyboard_slave_setup();
   }
   sei();
}

void keyboard_slave_loop(void) {
   matrix_init();

   while (1) {
      matrix_slave_scan();
   }
}

// this code runs before the usb and keyboard is initialized
void matrix_setup(void) {
    split_keyboard_setup();

    if (!has_usb()) {
        keyboard_slave_loop();
    }
}

D keyboards/handwired/not_so_minidox/split_util.h => keyboards/handwired/not_so_minidox/split_util.h +0 -17
@@ 1,17 0,0 @@
#pragma once

#include <stdbool.h>
#include "eeconfig.h"

#define SLAVE_I2C_ADDRESS           0x32

extern volatile bool isLeftHand;

// slave version of matix scan, defined in matrix.c
void matrix_slave_scan(void);

void split_keyboard_setup(void);
bool has_usb(void);
void keyboard_slave_loop(void);

void matrix_master_OLED_init (void);