refactor checkpoint: splitting MCU-specific code into arch/$MCU.[ch]

Phew, that's a lot of changes!  And there's still a lot more to do...

1 files changed, 147 insertions, 0 deletions

diff --git a/arch/attiny1616.c b/arch/attiny1616.c
new file mode 100644
index 0000000..3b170bb
--- /dev/null
+++ b/arch/attiny1616.c
@@ -0,0 +1,147 @@
+// arch/attiny1616.c: attiny1616 support functions
+// Copyright (C) 2023 Selene ToyKeeper
+// SPDX-License-Identifier: GPL-3.0-or-later
+#pragma once
+
+#include "arch/attiny1616.h"
+
+////////// clock speed / delay stuff //////////
+
+///// clock dividers
+// this should work, but needs further validation
+inline void clock_prescale_set(uint8_t n) {
+    cli();
+    CCP = CCP_IOREG_gc; // temporarily disable clock change protection
+    CLKCTRL.MCLKCTRLB = n; // Set the prescaler
+    while (CLKCTRL.MCLKSTATUS & CLKCTRL_SOSC_bm) {} // wait for clock change to finish
+    sei();
+}
+
+////////// ADC voltage / temperature //////////
+
+inline void mcu_set_admux_therm() {
+    ADC0.MUXPOS = ADC_MUXPOS_TEMPSENSE_gc;  // read temperature
+    ADC0.CTRLC = ADC_SAMPCAP_bm
+               | ADC_PRESC_DIV64_gc
+               | ADC_REFSEL_INTREF_gc; // Internal ADC reference
+}
+
+inline void mcu_set_admux_voltage() {
+    #ifdef USE_VOLTAGE_DIVIDER  // 1.1V / ADC input pin
+        // verify that this is correct!!!  untested
+        ADC0.MUXPOS = ADMUX_VOLTAGE_DIVIDER;  // read the requested ADC pin
+        ADC0.CTRLC = ADC_SAMPCAP_bm
+                   | ADC_PRESC_DIV64_gc
+                   | ADC_REFSEL_INTREF_gc; // Use internal ADC reference
+    #else  // VCC / 1.1V reference
+        ADC0.MUXPOS = ADC_MUXPOS_INTREF_gc;  // read internal reference
+        ADC0.CTRLC = ADC_SAMPCAP_bm
+                   | ADC_PRESC_DIV64_gc
+                   | ADC_REFSEL_VDDREF_gc; // Vdd (Vcc) be ADC reference
+    #endif
+}
+
+inline void mcu_adc_sleep_mode() {
+    set_sleep_mode(SLEEP_MODE_STANDBY);
+}
+
+inline void mcu_adc_start_measurement() {
+    ADC0.INTCTRL |= ADC_RESRDY_bm; // enable interrupt
+    ADC0.COMMAND |= ADC_STCONV_bm; // Start the ADC conversions
+}
+
+inline void mcu_adc_on() {
+    VREF.CTRLA |= VREF_ADC0REFSEL_1V1_gc; // Set Vbg ref to 1.1V
+    // Enabled, free-running (aka, auto-retrigger), run in standby
+    ADC0.CTRLA = ADC_ENABLE_bm | ADC_FREERUN_bm | ADC_RUNSTBY_bm;
+    // set a INITDLY value because the AVR manual says so (section 30.3.5)
+    // (delay 1st reading until Vref is stable)
+    ADC0.CTRLD |= ADC_INITDLY_DLY16_gc;
+    hwdef_set_admux_voltage();
+}
+
+inline void mcu_adc_off() {
+    ADC0.CTRLA &= ~(ADC_ENABLE_bm);  // disable the ADC
+}
+
+inline void mcu_adc_vect_clear() {
+    ADC0.INTFLAGS = ADC_RESRDY_bm; // clear the interrupt
+}
+
+inline uint16_t mcu_adc_result_temp() {
+    // Use the factory calibrated values in SIGROW.TEMPSENSE0 and
+    // SIGROW.TEMPSENSE1 to calculate a temperature reading in Kelvin, then
+    // left-align it.
+    int8_t sigrow_offset = SIGROW.TEMPSENSE1;  // Read signed value from signature row
+    uint8_t sigrow_gain = SIGROW.TEMPSENSE0;  // Read unsigned value from signature row
+    uint32_t temp = ADC0.RES - sigrow_offset;
+    temp *= sigrow_gain;  // Result might overflow 16 bit variable (10bit+8bit)
+    temp += 0x80;  // Add 1/2 to get correct rounding on division below
+    //temp >>= 8;  // Divide result to get Kelvin
+    //return temp << 6;  // left align it
+    return temp >> 2;  // left-aligned uint16_t
+}
+
+inline uint16_t mcu_adc_result_volts() {
+    // FIXME: set up ADC to use left-aligned values natively
+    return ADC0.RES << 6;  // voltage, force left-alignment
+}
+
+inline uint8_t mcu_adc_lsb() {
+    //return (ADCL >> 6) + (ADCH << 2);
+    return ADC0.RESL; // right aligned, not left... so should be equivalent?
+}
+
+
+////////// WDT //////////
+
+inline void mcu_wdt_active() {
+    RTC.PITINTCTRL = RTC_PI_bm;   // enable the Periodic Interrupt
+    while (RTC.PITSTATUS > 0) {}  // make sure the register is ready to be updated
+    RTC.PITCTRLA = RTC_PERIOD_CYC512_gc | RTC_PITEN_bm; // Period = 16ms, enable the PI Timer
+}
+
+inline void mcu_wdt_standby() {
+    RTC.PITINTCTRL = RTC_PI_bm;   // enable the Periodic Interrupt
+    while (RTC.PITSTATUS > 0) {}  // make sure the register is ready to be updated
+    RTC.PITCTRLA = (1<<6) | (STANDBY_TICK_SPEED<<3) | RTC_PITEN_bm; // Set period, enable the PI Timer
+}
+
+inline void mcu_wdt_stop() {
+    while (RTC.PITSTATUS > 0) {}  // make sure the register is ready to be updated
+    RTC.PITCTRLA = 0; // Disable the PI Timer
+}
+
+inline void mcu_wdt_vect_clear() {
+    RTC.PITINTFLAGS = RTC_PI_bm; // clear the PIT interrupt flag
+}
+
+
+////////// PCINT - pin change interrupt (e-switch) //////////
+
+inline void mcu_switch_vect_clear() {
+    // Write a '1' to clear the interrupt flag
+    SWITCH_INTFLG |= (1 << SWITCH_PIN);
+}
+
+inline void mcu_pcint_on() {
+    SWITCH_ISC_REG |= PORT_ISC_BOTHEDGES_gc;
+}
+
+inline void mcu_pcint_off() {
+    SWITCH_ISC_REG &= ~(PORT_ISC_gm);
+}
+
+
+////////// misc //////////
+
+void reboot() {
+    // put the WDT in hard reset mode, then trigger it
+    cli();
+    CCP = CCP_IOREG_gc;  // temporarily disable change protection
+    WDT.CTRLA = WDT_PERIOD_8CLK_gc;  // Enable, timeout 8ms
+    sei();
+    wdt_reset();
+    while (1) {}
+}
+