Fix a bunch of issues with ATTiny85 RTC implementation.
Decouple from Arduino libraries, use a small header file instead. Now compiles with plain avr-gcc. Still needs more work.
This commit is contained in:
Andrew Makousky
parent
097581b80a
commit
1f8d0f8163
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@ -1,6 +1,9 @@
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#include <avr/io.h>
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#include <avr/wdt.h>
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#include <avr/interrupt.h>
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#include <EEPROM.h>
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#include <avr/sleep.h>
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#include "arduino_sdef.h"
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/****************************************
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* *
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@ -17,101 +20,53 @@
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* *
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****************************************/
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const int ONE_SEC_PIN = 1; // A 1Hz square wave on PB5
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const int RTC_ENABLE_PIN = 5; // Active low chip enable on PB0
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const int SERIAL_DATA_PIN = 6; // Bi-directional serial data line on PB1
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const int SERIAL_CLOCK_PIN = 7; // Serial clock input on PB2
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/*********************************************
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* ATMEL ATTINY85 / ARDUINO *
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* *
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* +-\/-+ *
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* Ain0 (D 5) PB5 1| |8 Vcc *
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* Ain3 (D 3) PB3 2| |7 PB2 (D 2) Ain1 *
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* Ain2 (D 4) PB4 3| |6 PB1 (D 1) pwm1 *
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* GND 4| |5 PB0 (D 0) pwm0 *
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* +----+ *
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*********************************************/
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const int PRAM_SIZE = 256; // Mac Plus used the xPRAM chip with 256 bytes, time is a separate 4 additional bytes
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//const int PRAM_SIZE = 20; // Models earlier than the Plus had 20 bytes of PRAM
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const int ONE_SEC_PIN = 5; // A 1Hz square wave on PB5
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const int RTC_ENABLE_PIN = 0; // Active low chip enable on PB0
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const int SERIAL_DATA_PIN = 1; // Bi-directional serial data line on PB1
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const int SERIAL_CLOCK_PIN = 2; // Serial clock input on PB2
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#if NoXPRAM
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// Models earlier than the Plus had 20 bytes of PRAM
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const int PRAM_SIZE = 20;
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#else
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// Mac Plus used the xPRAM chip with 256 bytes
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const int PRAM_SIZE = 256;
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#endif
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volatile boolean lastSerClock = 0;
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volatile byte serialBitNum = 0;
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volatile byte address = 0;
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volatile byte serialData = 0;
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enum SerialStateType { SERIAL_DISABLED, RECEIVING_COMMAND, SENDING_DATA, RECEIVING_DATA };
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enum SerialStateType { SERIAL_DISABLED, RECEIVING_COMMAND,
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SENDING_DATA, RECEIVING_DATA };
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volatile SerialStateType serialState = SERIAL_DISABLED;
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volatile unsigned long seconds = 0;
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volatile byte pram[PRAM_SIZE] = {}; // 256 Bytes of PRAM, the first four of which count the number of seconds since 1/1/1904
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/*
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* The following is potential locations of various bits of PRAM data, none of this is in any way certain:
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* Sound volume is in pram[0x08]
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* Alert sound is in param[0x7c - 0x7d]
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* Machine location and timezone is in pram[0xE4 - 0xEF]
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*/
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/*
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* An interrupt to both increment the seconds counter and generate the square wave
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*/
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void halfSecondInterrupt() {
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PINB = 1<<PINB0; // Flip the one-second pin
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if(!(PINB & (1<<PINB0))) { // If the one-second pin is low
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seconds++;
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}
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}
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/*
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* The actual serial communication can be done in the main loop, this way the clock still gets incremented
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*/
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void handleRTCEnableInterrupt() {
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serialBitNum = 0;
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address = 0;
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serialData = 0;
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if(!(PINB&(1<<RTC_ENABLE_PIN))){ // Simulates a falling interrupt
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serialState = RECEIVING_COMMAND;
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// enableRTC = true;
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} else { // Simulates a rising interrupt
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clearState();
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}
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}
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void clearState() {
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DDRB &= ~(1<<DDB1); // Return the pin to input mode
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PORTB |= (1<<PORTB1); // Set pullup resistor
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serialState = SERIAL_DISABLED;
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serialBitNum = 0;
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address = 0;
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serialData = 0;
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}
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/*
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* The ATtiny has EEPROM, lets use it to store the contents of PRAM in case of power failure,
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* this is an improvement over the original, still a good idea to keep the chip powered by a
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* battery or supercapacitor so that the clock continues to advance.
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*
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*/
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void savePRAM() {
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noInterrupts(); // Don't update the seconds counter while we're saving it to ROM, probably unnecessary
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for(int i = 0; i < 4; i++) {
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EEPROM.update(i,(seconds>>(8*i))&0xff);
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}
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interrupts(); // Go ahead and interrupt us while we save the rest
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for(int i = 0; i < PRAM_SIZE; i++) {
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EEPROM.update(i+4,pram[i]);
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}
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}
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void goToSleep() {
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bitClear(MCUCR,SM0); // The two SM bits must be set to 00 to enter idle mode
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bitClear(MCUCR,SM1); // Sleeping in other modes will disable the timer
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bitSet(MCUCR,SE);
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__asm__("sleep" "\n\t");
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bitClear(MCUCR,SE);
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}
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// Number of seconds since midnight, January 1, 1904. Clock is
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// initialized to January 1st, 1984? Or is this done by the ROM when
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// the validity status is invalid?
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volatile unsigned long seconds = 60 * 60 * 24 * (365 * 4 + 1) * 20;
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volatile byte pram[PRAM_SIZE] = {}; // PRAM initialized as zeroed data
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void setup() {
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noInterrupts(); // Disable interrupts while we set things up
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pinMode(ONE_SEC_PIN, OUTPUT); // The 1Hz square wave (used, I think, for interrupts elsewhere in the system)
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pinMode(RTC_ENABLE_PIN, INPUT_PULLUP); // The processor pulls this pin low when it wants access
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pinMode(SERIAL_CLOCK_PIN, INPUT_PULLUP); // The serial clock is driven by the processor
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pinMode(SERIAL_DATA_PIN, INPUT_PULLUP); // We'll need to switch this to output when sending data
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pinModePB(ONE_SEC_PIN, OUTPUT); // The 1Hz square wave (used, I think, for interrupts elsewhere in the system)
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pinModePB(RTC_ENABLE_PIN, INPUT_PULLUP); // The processor pulls this pin low when it wants access
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pinModePB(SERIAL_CLOCK_PIN, INPUT_PULLUP); // The serial clock is driven by the processor
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pinModePB(SERIAL_DATA_PIN, INPUT_PULLUP); // We'll need to switch this to output when sending data
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wdt_disable(); // Disable watchdog
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bitSet(ACSR,ACD); // Disable Analog Comparator, don't need it, saves power
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bitSet(PRR,PRTIM1); // Disable Timer 1, only using Timer 0, Timer 1 uses around ten times as much current
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@ -121,38 +76,77 @@ void setup() {
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bitSet(GIMSK,PCIE); // Pin Change Interrupt Enable
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bitSet(PCMSK,PCINT0); // turn on RTC enable interrupt
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// for(int i = 0; i < 4; i++) {
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// seconds += ((unsigned long)EEPROM.read(i))<<(8*i);
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// }
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// for(int i = 0; i < PRAM_SIZE; i--) { // Preload PRAM with saved values
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// pram[i] = EEPROM.read(i+4);
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// }
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//set up timer
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bitSet(GTCCR,TSM); // Turns off timers while we set it up
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bitSet(TIMSK,TOIE0); // Set Timer/Counter0 Overflow Interrupt Enable
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TCCR0B = 0b111; // Set prescaler, 32,768Hz/64 = 512Hz, fills up the 8-bit counter (256) once every half second
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TCNT0 = 0; // Clear the counter
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bitClear(GTCCR,TSM); // Turns timers back on
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interrupts(); //We're done setting up, enable those interrupts again
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}
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void clearState() {
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// Return the pin to input mode, set pullup resistor
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pinModePB(SERIAL_DATA_PIN, INPUT_PULLUP);
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serialState = SERIAL_DISABLED;
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lastSerClock = 0;
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serialBitNum = 0;
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address = 0;
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serialData = 0;
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}
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/*
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* An interrupt to both increment the seconds counter and generate the
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* square wave
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*/
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void halfSecondInterrupt() {
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PINB = 1<<ONE_SEC_PIN; // Flip the one-second pin
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if(!(PINB&(1<<ONE_SEC_PIN))) { // If the one-second pin is low
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seconds++;
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}
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}
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/*
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* The actual serial communication can be done in the main loop, this
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* way the clock still gets incremented
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*/
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void handleRTCEnableInterrupt() {
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if(!(PINB&(1<<RTC_ENABLE_PIN))){ // Simulates a falling interrupt
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serialState = RECEIVING_COMMAND;
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// enableRTC = true;
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}
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}
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void loop() {
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if(digitalRead(RTC_ENABLE_PIN)) {
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if((PINB&(1<<RTC_ENABLE_PIN))) {
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clearState();
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goToSleep();
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} else if(digitalRead(SERIAL_CLOCK_PIN)) {
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switch(serialState) {
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set_sleep_mode(0); // Sleep mode 0 == default, timers still running.
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sleep_mode();
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} else {
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// Compute rising and falling edge trigger flags for the serial
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// clock.
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boolean curSerClock = PINB&(1<<SERIAL_CLOCK_PIN);
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boolean serClockRising = !lastSerClock && curSerClock;
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boolean serClockFalling = lastSerClock && !curSerClock;
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lastSerClock = curSerClock;
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// TODO FIXME: We need to implement an artificial delay between
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// the clock's rising edge and the update of the data line output
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// because of a bug in the ROM. Is 10 microseconds a good wait
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// time?
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if(serClockRising) {
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switch(serialState) {
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case RECEIVING_COMMAND:
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bitWrite(address,7-serialBitNum,digitalRead(SERIAL_DATA_PIN));
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bitWrite(address,7-serialBitNum,digitalReadPB(SERIAL_DATA_PIN));
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serialBitNum++;
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if(serialBitNum > 7) {
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boolean writeRequest = address&(1<<7); // the MSB determines if it's a write request or not
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address &= ~(1<<7); // Discard the first bit, it's not part of the address
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serialBitNum = 0;
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if(writeRequest) {
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if(writeRequest) {
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serialState = RECEIVING_DATA;
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serialBitNum = 0;
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} else {
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@ -163,13 +157,13 @@ void loop() {
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}
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serialState = SENDING_DATA;
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serialBitNum = 0;
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pinMode(SERIAL_DATA_PIN, OUTPUT); // Set the pin to output mode
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pinModePB(SERIAL_DATA_PIN, OUTPUT); // Set the pin to output mode
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}
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}
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break;
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case RECEIVING_DATA:
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bitWrite(serialData,7-serialBitNum,digitalRead(SERIAL_DATA_PIN));
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bitWrite(serialData,7-serialBitNum,digitalReadPB(SERIAL_DATA_PIN));
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serialBitNum++;
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if(serialBitNum > 7) {
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if(address < 4) {
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@ -179,17 +173,17 @@ void loop() {
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} else {
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pram[address] = serialData;
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}
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// savePRAM();
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clearState();
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}
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break;
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case SENDING_DATA:
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digitalWrite(SERIAL_DATA_PIN,bitRead(serialData,7-serialBitNum));
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digitalWritePB(SERIAL_DATA_PIN,bitRead(serialData,7-serialBitNum));
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serialBitNum++;
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if(serialBitNum > 7) {
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clearState();
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}
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}
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}
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}
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}
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@ -204,3 +198,14 @@ ISR(PCINT0_vect) {
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ISR(TIMER0_OVF) {
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halfSecondInterrupt();
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}
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// Arduino main function.
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int main(void) {
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setup();
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for (;;) {
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loop();
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}
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return 0;
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}
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@ -0,0 +1,78 @@
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#ifndef ARDUINO_SDEF_H
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#define ARDUINO_SDEF_H
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/********************************************************************/
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// Simplified Arduino.h definitions.
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typedef bool boolean;
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typedef uint8_t byte;
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#define HIGH 0x1
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#define LOW 0x0
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#define INPUT 0x0
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#define OUTPUT 0x1
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#define INPUT_PULLUP 0x2
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#define interrupts() sei()
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#define noInterrupts() cli()
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#define bitRead(value, bit) (((value) >> (bit)) & 0x01)
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#define bitSet(value, bit) ((value) |= (1UL << (bit)))
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#define bitClear(value, bit) ((value) &= ~(1UL << (bit)))
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#define bitWrite(value, bit, bitvalue) ((bitvalue) ? bitSet(value, bit) : bitClear(value, bit))
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// END simplified Arduino.h definitions.
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/********************************************************************/
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// Simplified wiring_digital.c definitions.
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// Only suitable for single source code file projects.
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void pinModePB(uint8_t portbit, uint8_t mode)
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{
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uint8_t bit = _BV(portbit);
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if (mode == INPUT) {
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uint8_t oldSREG = SREG;
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cli();
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DDRB &= ~bit;
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PORTB &= ~bit;
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SREG = oldSREG;
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} else if (mode == INPUT_PULLUP) {
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uint8_t oldSREG = SREG;
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cli();
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DDRB &= ~bit;
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PORTB |= bit;
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SREG = oldSREG;
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} else {
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uint8_t oldSREG = SREG;
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cli();
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DDRB |= bit;
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SREG = oldSREG;
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}
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}
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void digitalWritePB(uint8_t portbit, uint8_t val)
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{
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uint8_t bit = _BV(portbit);
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uint8_t oldSREG = SREG;
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cli();
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if (val == LOW) {
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PORTB &= ~bit;
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} else {
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PORTB |= bit;
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}
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SREG = oldSREG;
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}
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int digitalReadPB(uint8_t portbit)
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{
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uint8_t bit = _BV(portbit);
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if (PINB & bit) return HIGH;
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return LOW;
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}
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// END simplified wiring_digital.c definitions.
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#endif /* not ARDUINO_SDEF_H */
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@ -0,0 +1,3 @@
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#! /bin/sh
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avr-gcc -c -Os -mmcu=attiny85 MacRTC.cpp
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avr-gcc -mmcu=attiny85 -o MacRTC.axf MacRTC.o
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