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[z180-stamp.git] / avr / main.c

/*
 */


#include "common.h"

#include <util/delay.h>
#include <avr/interrupt.h>
#include <stdlib.h>
#include <stdio.h>

#include "config.h"
#include "debug.h"
#include "z80-if.h"
#include "i2c.h"
#include "con-utils.h"
#include "serial.h"
#include "timer.h"
#include "cli.h"
#include "env.h"

#define udelay(n)  _delay_us(n)

static uint8_t mcusr;

/*--------------------------------------------------------------------------*/
#if DEBUG

__attribute__ ((naked)) __attribute__ ((section (".init3")))
void preset_ram (void)
{
	for (uint8_t *p = RAMSTART; p <= (uint8_t *) RAMEND; p++)
		*p = 0xdd;

}

static const FLASH char * const FLASH rreasons[] = {
			FSTR("Power on"),
			FSTR("External"),
			FSTR("Brown out"),
			FSTR("Watchdog"),
			FSTR("JTAG"),
		};

static
void print_reset_reason(void)
{
	uint8_t r = mcusr & 0x1f;
	const FLASH char * const FLASH *p = rreasons;

	printf_P(PSTR("### Reset reason(s): %s"), r ? "" : "none");
	for ( ; r; p++, r >>= 1) {
		if (r & 1) {
			my_puts_P(*p);
			if (r & ~1)
				printf_P(PSTR(", "));
		}
	}
	printf_P(PSTR(".\n"));
}

#endif

static
void setup_avr(void)
{
	/* save and clear reset reason(s) */
	/* TODO: move to init section? */
	mcusr = MCUSR;
	MCUSR = 0;

	/* WD */

	/* CPU */

	/* Disable JTAG Interface regardless of the JTAGEN fuse setting. */
	MCUCR = _BV(JTD);
	MCUCR = _BV(JTD);

	/* Disable peripherals. Enable individually in respective init function. */
	PRR0 = _BV(PRTWI) |
		_BV(PRTIM2) | _BV(PRTIM0) | _BV(PRTIM1) |
		_BV(PRSPI) | _BV(PRUSART0) | _BV(PRADC);

	PRR1 = _BV(PRTIM5) | _BV(PRTIM4) | _BV(PRTIM3) |
		_BV(PRUSART3) | _BV(PRUSART2) | _BV(PRUSART1);


	/* disable analog comparator */
	ACSR = _BV(ACD);
	/* Ports */

	/* Clock */
	CLKPR = _BV(CLKPCE);
	CLKPR = 0;

	/* Timer */
	PRR1 &= ~_BV(PRTIM3);
	OCR3A = F_CPU / 1000 - 1;	/* Timer3: 1000Hz interval (OC3A) */
	TCCR3B = (0b01<<WGM32)|(0b001<<CS30); /* CTC Mode, Prescaler 1 */
	TIMSK3 = _BV(OCIE3A);		/* Enable TC2.oca interrupt */
}

static
int reset_reason_is_power_on(void)
{
	return (mcusr & _BV(PORF)) != 0;
}

/*--------------------------------------------------------------------------*/

/* Stored value of bootdelay, used by autoboot_command() */
static int  stored_bootdelay;


/***************************************************************************
 * Watch for 'delay' seconds for autoboot stop.
 * returns: 0 - no key, allow autoboot
 *          1 - got key, abort
 */

static int abortboot(int  bootdelay)
{
	int abort = 0;
	uint32_t ts;

	if (bootdelay >= 0)
		printf_P(PSTR("Hit any key to stop autoboot: %2d "), bootdelay);

#if defined CONFIG_ZERO_BOOTDELAY_CHECK
	/*
	 * Check if key already pressed
	 * Don't check if bootdelay < 0
	 */
	if (bootdelay >= 0) {
		if (tstc()) {	/* we got a key press	*/
			(void) my_getchar();  /* consume input	*/
			my_puts_P(PSTR("\b\b\b 0"));
			abort = 1;	/* don't auto boot	*/
		}
	}
#endif

	while ((bootdelay > 0) && (!abort)) {
		--bootdelay;
		/* delay 1000 ms */
		ts = get_timer(0);
		do {
			if (tstc()) {	/* we got a key press	*/
				abort  = 1;	/* don't auto boot	*/
				bootdelay = 0;	/* no more delay	*/
				break;
			}
			udelay(10000);
		} while (!abort && get_timer(ts) < 1000);

		printf_P(PSTR("\b\b\b%2d "), bootdelay);
	}

	putchar('\n');

	return abort;
}

static
const char *bootdelay_process(void)
{
	char *s;
	int bootdelay;

	bootdelay = (int) getenv_ulong(PSTR(ENV_BOOTDELAY), 10, CONFIG_BOOTDELAY);


	debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);
	_delay_ms(20);

	s = getenv(PSTR(ENV_BOOTCMD));
	stored_bootdelay = bootdelay;
	return s;
}

static
void autoboot_command(const char *s)
{
	debug("### main_loop: bootcmd=\"%s\"\n", s ? s : PSTR("<UNDEFINED>"));
	_delay_ms(20);

	if (stored_bootdelay != -1 && s && !abortboot(stored_bootdelay)) {
		run_command_list(s, -1);
	}
}


static
void main_loop(void)
{
	const char *s;

	s = bootdelay_process();
	autoboot_command(s);
	cli_loop();
}

int main(void)
{

	setup_avr();
	z80_setup_bus();

	env_init();

	if (reset_reason_is_power_on())
		_delay_ms(CONFIG_PWRON_DELAY);

	serial_setup(getenv_ulong(PSTR(ENV_BAUDRATE), 10, CONFIG_BAUDRATE));
	sei();

#if DEBUG
	debug("\n=========================<  (RE)START DEBUG  >=========================\n");
	print_reset_reason();
#endif

#if DEBUG
	unsigned long i_speed = getenv_ulong(PSTR("i2c_clock"), 10, CONFIG_SYS_I2C_CLOCK);
	debug("### Setting I2C clock Frequency to %lu Hz.\n", i_speed);
	i2c_init(i_speed);
#else
	i2c_init(CONFIG_SYS_I2C_CLOCK);
#endif

	printf_P(PSTR("\nATMEGA1281+Z8S180 Stamp Monitor\n\n"));


	main_loop();
}