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vectorscope / scopeclock.c

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/**
 * \file Dual DAC outputs for driving a vector scope.
 *
 */

#include <avr/io.h>
#include <avr/pgmspace.h>
#include <avr/interrupt.h>
#include <stdint.h>
#include <string.h>
#include <util/delay.h>
#include "usb_serial.h"
#include "bits.h"

void send_str(const char *s);
uint8_t recv_str(char *buf, uint8_t size);
void parse_and_execute_command(const char *buf, uint8_t num);

static uint8_t
hexdigit(
	uint8_t x
)
{
	x &= 0xF;
	if (x < 0xA)
		return x + '0' - 0x0;
	else
		return x + 'A' - 0xA;
}


static uint8_t
printable(
	uint8_t x
)
{
	if ('A' <= x && x <= 'Z')
		return 1;
	if ('a' <= x && x <= 'z')
		return 1;
	if ('0' <= x && x <= '9')
		return 1;
	if (x == ' ')
		return 1;

	return 0;
}


int main(void)
{
	// set for 16 MHz clock
#define CPU_PRESCALE(n) (CLKPR = 0x80, CLKPR = (n))
	CPU_PRESCALE(0);

	// Disable the ADC
	ADMUX = 0;

	// initialize the USB, and then wait for the host
	// to set configuration.  If the Teensy is powered
	// without a PC connected to the USB port, this 
	// will wait forever.
	usb_init();
	while (!usb_configured()) /* wait */ ;
	_delay_ms(1000);

	// wait for the user to run their terminal emulator program
	// which sets DTR to indicate it is ready to receive.
	while (!(usb_serial_get_control() & USB_SERIAL_DTR))
		continue;

	// discard anything that was received prior.  Sometimes the
	// operating system or other software will send a modem
	// "AT command", which can still be buffered.
	usb_serial_flush_input();

	DDRB = 0xFF;
	DDRD = 0xFF;
	PORTB = 128;
	PORTD = 0;

	uint8_t off = 0;
	char buf[32];

	uint8_t dx = 1;
	uint8_t dy = 1;

	while (1)
	{
#if 0
		if (dy)
		{
			if (PORTB == 0xFF)
			{
				dy = 0;
				if (dx)
				{
					if (PORTD == 0xFF)
						dx = 0;
					else
						PORTD += 2;
				} else {
					if (PORTD == 0)
						dx = 1;
					else
						PORTD--;
				}
			}
			else
				PORTB++;
		} else {
			if (PORTB == 0)
				dy = 1;
			else
				PORTB--;
		}
#endif
		PORTB += 1;
		PORTD += 1;


		buf[off++] = hexdigit(PORTB >> 4);
		buf[off++] = hexdigit(PORTB >> 0);
		buf[off++] = '\r';
		buf[off++] = '\n';

		usb_serial_write(buf, off);
		off = 0;
		_delay_ms(1);
	}
}


// Send a string to the USB serial port.  The string must be in
// flash memory, using PSTR
//
void send_str(const char *s)
{
	char c;
	while (1) {
		c = pgm_read_byte(s++);
		if (!c) break;
		usb_serial_putchar(c);
	}
}