pinephone-keyboard/firmware/main.c

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/**
* Pinephone Keyboard Firmware
*
* Copyright (C) 2021 Ondřej Jirman <megi@xff.cz>
*
* 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 3 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 <stdint.h>
#include <string.h>
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#include <em85f684a.h>
// configuration (we can make this runtime configurable via i2c)
// polled input mode is necessary if some rows are always on
#define POLL_INPUT 1
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#define BIT(n) (1u << (n))
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// timers clock is 2 MHz so we need to wait for 2000 ticks to get delay of 1ms
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#define T0_SET_TIMEOUT(n) { \
TL0 = 0x00; \
TH0 = (0x10000u - n) >> 8; \
TL0 = (0x10000u - n) & 0xff; \
}
#define T1_SET_TIMEOUT(n) { \
TL1 = 0x00; \
TH1 = (0x10000u - n) >> 8; \
TL1 = (0x10000u - n) & 0xff; \
}
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#define delay_us(n) { \
TL0 = 0x00; \
TF0 = 0; \
TH0 = (0x10000u - 2 * n) >> 8; \
TL0 = (0x10000u - 2 * n) & 0xff; \
while (!TF0); \
}
static __sbit p6_changed = 0;
static __sbit run_tasks = 0;
// we use this interrupt for wakeup from sleep on input change
void pinchange_interupt(void) __interrupt(IRQ_PINCHANGE)
{
uint8_t saved_page = PAGESW;
PAGESW = 0;
if (P0_ICEN & BIT(1))
p6_changed = 1;
// clear input change flags
P0_ICEN = BIT(5);
PAGESW = saved_page;
}
// we use this interrupt as a scheduling tick (wakeup from sleep)
void timer1_interupt(void) __interrupt(IRQ_TIMER1)
{
run_tasks = 1;
// 20 ms
T1_SET_TIMEOUT(40000);
TF1 = 0;
}
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// Keyboard has 12 columns and 6 rows directly connected to GPIOs.
//
// C1 P95
// C2 P96
// C3 P97
// C4 P50
// C5 P51
// C6 P52
// C7 P53
// C8 P54
// C9 P55
// C10 P56
// C11 P57
// C12 P80 (also USB IAP trigger when pulled low)
//
// R1 P60
// R2 P61
// R3 P62
// R4 P63
// R5 P64
// R6 P65
//
// INT P90
// SCL P92
// SDA P93
//
// We will want to keep keyboard controller asleep unless some key is
// pressed. If a key is pressed, the controller will continuously scan
// for further pressed keys. When all keys are released, the controller
// can go back to sleep.
//
// For this to work, we'll use port 6 ability to wake up the controller
// on change.
//
// During sleep:
// - all columns will be set to low state
// - all rows will have pull-up enabled
// - when user presses any key, row state will change to low and
// the controller will wake up
//
// During active state:
// - all columns will be put to hi-Z state, except for the currently
// scanned one, which will be in low state
// - state of rows will be read, and will indicate state of keys
// in the selected column (0 = pressed, 1 = not pressed)
//
// De-bouncing:
// - scanning will happen in 5ms intervals and only if the two
// consecutive scans match, will the result be considered valid
//
// Configure GPIO for keyboard key scanning
//
// Switch to idle state
//
// In this state we can use keyscan_idle_is_pressed() to detect whether
// any key is pressed, and switch to active mode via keyscan_active().
//
void keyscan_idle(void)
{
// enable output low on all columns (P9[7:5] P5[7:0] P8[0])
PAGESW = 0;
P5 = 0;
P8 &= 0xfe;
P9 &= 0x1f;
#if POLL_INPUT
// make all columns an input, hi-Z (saves power)
P0_P5M0 = ~0x00u;
P0_P8M0 |= ~0xfeu;
PAGESW = 1;
P1_P9M0 |= ~0x1fu;
ICIE = 0;
p6_changed = 0;
#else
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P0_P5M0 = 0x00;
P0_P8M0 &= 0xfe;
PAGESW = 1;
P1_P9M0 &= 0x1f;
// enable input change interrupt on port6 and clear the interrupt flag after
// things stabilize
delay_us(10);
PAGESW = 0;
p6_changed = 0;
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P0_ICEN = BIT(5);
ICIE = 1;
#endif
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}
uint8_t keyscan_idle_is_pressed(void)
{
return ~P6 & 0x3f;
}
//
// Switch to active mode.
//
// In this state, we can call keyscan_scan() to perform a scan.
//
void keyscan_active(void)
{
// put all columns to hi-Z (P9[7:5] P5[7:0] P8[0])
// disable input change interrupt
ICIE = 0;
PAGESW = 0;
P5 = 0;
P8 &= 0xfe;
P9 &= 0x1f;
// make all columns an input (hi-Z) in preparation for individual
// column scanning
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P0_P5M0 = ~0x00u;
P0_P8M0 |= ~0xfeu;
PAGESW = 1;
P1_P9M0 |= ~0x1fu;
}
// XXX: do we need to debounce in the scan function?
// XXX: it looks like that there should be no bouncing going on mechanically
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// 12 byte storage required
uint8_t keyscan_scan(uint8_t* res)
{
uint8_t pin, mask = 0, row;
// for each column:
// - output low on column
// - wait (for voltage to stabilize)
// - read rows
// - turn column back to hi-Z
PAGESW = 1;
for (pin = 5; pin <= 7; pin++) {
P1_P9M0 &= ~BIT(pin);
delay_us(3);
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row = ~P6 & 0x3f;
mask |= row;
*res++ = row;
P1_P9M0 |= BIT(pin);
}
PAGESW = 0;
for (pin = 0; pin <= 7; pin++) {
P0_P5M0 &= ~BIT(pin);
delay_us(3);
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row = ~P6 & 0x3f;
mask |= row;
*res++ = row;
P0_P5M0 |= BIT(pin);
}
P0_P8M0 &= ~BIT(0);
delay_us(3);
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row = ~P6 & 0x3f;
mask |= row;
*res++ = row;
P0_P8M0 |= BIT(0);
return mask;
}
void ext_int_assert(void)
{
P90 = 0;
PAGESW = 1;
P1_P9M0 &= ~BIT(0);
}
void ext_int_deassert(void)
{
P90 = 0;
PAGESW = 1;
P1_P9M0 |= BIT(0);
}
#define I2C_N_REGS 16
static uint8_t i2c_transfer = 0x00;
static uint8_t i2c_addr = 0;
static uint8_t i2c_regs[I2C_N_REGS] = {0xaa, 0x55};
static uint8_t i2c_cmd[I2C_N_REGS];
static uint8_t i2c_cmd_len = 0;
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//XXX: how to determine end of I2C transaction from the interrupt?
//XXX: we need this to be able to determine when it's safe to go back to sleep/power down
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void i2c_b_interupt(void) __interrupt(IRQ_I2CB)
{
uint8_t saved_page = PAGESW;
uint8_t tmp;
PAGESW = 0;
// handle TX
if (P0_I2CBINT & BIT(7)) {
if (i2c_addr < 16)
P0_I2CBDB = i2c_regs[i2c_addr++];
else
P0_I2CBDB = 0xff;
P0_I2CBCR1 &= ~BIT(7); // clear data pending
P0_I2CBINT &= ~BIT(7);
}
// handle RX
if (P0_I2CBINT & BIT(6)) {
tmp = P0_I2CBDB;
if (i2c_cmd_len < 16)
i2c_cmd[i2c_cmd_len++] = tmp;
PAGESW = 0;
P0_I2CBCR1 &= ~BIT(7); // clear data pending
P0_I2CBINT &= ~BIT(6);
}
// handle stop condition
if (P0_I2CBINT & BIT(4)) {
i2c_addr = 0;
i2c_cmd_len = 0;
P0_I2CBINT &= ~BIT(4);
}
PAGESW = saved_page;
}
//
// Slave mode I2C for communication with the SoC
//
// - address is 0x15
// - 400kHz
// - interrupts are used to handle tx/rx/end of transaction (stop bit)
//
void i2c_slave_init(void)
{
PAGESW = 0;
// setup I2C B for slave mode
//P0_I2CBCR1 = 0x20;
//P0_I2CBCR2 = 0x07 << 1 | 0x01; // 400kHz mode, enable I2C B controller, enable
P0_I2CBCR1 = 0x00;
P0_I2CBCR2 = 0x07 << 1 | BIT(0); // 100kHz mode, enable I2C B controller, enable
// setup I2C address
P0_I2CBDAH = 0x00;
P0_I2CBDAL = 0x15;
P0_I2CBINT = BIT(5); // enable I2C B stop interrupt
P0_EIE3 |= BIT(5); // enable I2C B interrupt
}
void main(void)
{
uint8_t scan_active = 0;
PAGESW = 0;
// setup interrupts
EA = 0;
IE = 0;
P0_EIE1 = 0;
P0_EIE2 = 0;
P0_EIE3 = 0;
// set CPU clock to normal (high frequency) mode
// [7] = power down HS clock in low speed mode - 1: yes 0: no
// [2:1] = high speed clock pre-divider - 1: /4 2: /2 3: /1
// [0] = cpu clock mode 1: high speed mode 0: low speed mode
CKCON1 = (CKCON1 & ~0x87u) | 0x07; // 0x87
// set timer 1 and timer 0 clock source to sysclk/12 (2 MHz)
CKCON0 = 0x00;
// wait until high speed clock is stable
while (!(CKCON0 & BIT(1)));
// set both timers to 16-bit counter modes
TMOD = 0x11;
// enable both timers
TCON = 0x50;
// setup watchdog (timer base is 8ms, prescaler sets up timeout /128 = ~1s)
// P0_WDTCR = 0x87; // enable watchdog ~1s
// P0_WDTKEY = 0x4e; // reset watchdog
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P0_WDTCR = 0x07; // disable watchdog ~1s
P0_WDTKEY = 0xb1; // disable watchdog
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// power down unused peripherlas
P0_DEVPD1 |= BIT(6) | BIT(5) | BIT(3) | BIT(1); // PWM A, timer 3, SPI, LVD
P0_DEVPD2 |= BIT(6) | BIT(3) | BIT(0); // PWM C, PWM B, I2C A
P0_DEVPD3 |= BIT(2) | BIT(1) | BIT(0); // PWM E, PWM D, PWM F
// keep UART, SPI, and I2C A in reset
//P0_PRST |= BIT(0) | BIT(2) | BIT(3);
// enable pullups only all port 6 pins and make those pins into input
PAGESW = 0;
P0_PHCON0 = 0x00;
P0_PHCON1 = 0xff; // port 6 pull-up enable
P0_P6M0 = 0xff; // port 6 input
PAGESW = 1;
P1_PHCON2 = 0x00;
// enable auto-tuning internal RC oscillator based on USB SOF packets
//P1_IRCCTRL &= ~BIT(1); // disable manual trim
i2c_slave_init();
T1_SET_TIMEOUT(40000);
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// enable interrupts
ET1 = 1;
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EA = 1;
ext_int_deassert();
#if POLL_INPUT
keyscan_active();
#else
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keyscan_idle();
#endif
uint8_t asserted = 0;
//uint16_t ticks = 0;
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while (1) {
if (!run_tasks) {
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// power down (timers don't work in power-down)
//PCON |= BIT(1);
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// go to idle CPU mode when there's nothing to do (doesn't help much)
// switching to LOSC may work better
//PCON |= BIT(0);
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__asm__("nop");
continue;
}
//ticks++;
run_tasks = 0;
#if POLL_INPUT
// every 10ms we will scan the keyboard keys state and check for changes
uint8_t keys[12];
uint8_t active_rows = keyscan_scan(keys);
if (active_rows) {
// pressing FN+PINE+F switches to flashing mode (keys 1:2 3:5 5:2, electrically)
if (keys[0] & BIT(2) && keys[2] & BIT(5) && keys[4] & BIT(2)) {
EA = 0;
__asm__("mov r6,#0x5a");
__asm__("mov r7,#0xe7");
__asm__("ljmp 0x0118");
}
// check for changes
if (!memcmp(i2c_regs + 4, keys, 12))
continue;
// signal interrupt
memcpy(i2c_regs + 4, keys, 12);
ext_int_assert();
delay_us(100);
ext_int_deassert();
}
#else
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if (scan_active) {
uint8_t active_rows = keyscan_scan(i2c_regs + 4);
if (!active_rows) {
scan_active = 0;
keyscan_idle();
// power down
//PCON |= BIT(1);
//__asm__("nop");
}
// pressing FN+PINE+F switches to flashing mode (keys 1:2 3:5 5:2, electrically)
if (i2c_regs[4 + 0] & BIT(2) && i2c_regs[4 + 2] & BIT(5) && i2c_regs[4 + 4] & BIT(2)) {
EA = 0;
__asm__("mov r6,#0x5a");
__asm__("mov r7,#0xe7");
__asm__("ljmp 0x0118");
}
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continue;
}
if (keyscan_idle_is_pressed()) {
scan_active = 1;
keyscan_active();
}
#endif
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}
}