--- /dev/null
+/*
+ * Copyright © 2011 Keith Packard <keithp@keithp.com>
+ *
+ * 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; version 2 of the License.
+ *
+ * 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, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#define TEENSY 0
+#if TEENSY
+#define F_CPU 16000000UL // 16 MHz
+#else
+#define F_CPU 8000000UL // 8 MHz
+#endif
+#include <util/delay.h>
+
+#define LEDOUT PORTB7
+#define LEDPORT PORTB
+#define LEDDDR DDRB
+#define LEDDDRPIN DD7
+
+static void
+adc_start(void);
+
+ISR(TIMER1_COMPA_vect)
+{
+ adc_start();
+}
+
+static void
+timer1_init(void)
+{
+ TCCR1A = ((0 << WGM11) | /* CTC mode, OCR1A */
+ (0 << WGM10)); /* CTC mode, OCR1A */
+ TCCR1B = ((0 << ICNC1) | /* no input capture noise canceler */
+ (0 << ICES1) | /* input capture on falling edge (don't care) */
+ (0 << WGM13) | /* CTC mode, OCR1A */
+ (1 << WGM12) | /* CTC mode, OCR1A */
+ (3 << CS10)); /* clk/64 from prescaler */
+
+#if TEENSY
+ OCR1A = 2500; /* 16MHz clock */
+#else
+ OCR1A = 1250; /* 8MHz clock */
+#endif
+
+ TIMSK1 = (1 << OCIE1A); /* Interrupt on compare match */
+}
+
+static void
+clock_init(void)
+{
+ /* disable RC clock */
+ CLKSEL0 &= ~(1 << RCE);
+
+ /* Disable PLL */
+ PLLCSR &= ~(1 << PLLE);
+
+ /* Enable external clock */
+ CLKSEL0 |= (1 << EXTE);
+
+ /* wait for external clock to be ready */
+ while ((CLKSTA & (1 << EXTON)) == 0)
+ ;
+
+ /* select external clock */
+ CLKSEL0 |= (1 << CLKS);
+
+ /* Disable the clock prescaler */
+ cli();
+ CLKPR = (1 << CLKPCE);
+ CLKPR = 0;
+ sei();
+
+ /* Set up the PLL to use the crystal */
+
+ /* Use primary system clock as PLL source */
+ PLLFRQ = ((0 << PINMUX) | /* Use primary clock */
+ (0 << PLLUSB) | /* No divide by 2 for USB */
+ (0 << PLLTM0) | /* Disable high speed timer */
+ (0x4 << PDIV0)); /* 48MHz PLL clock */
+
+ /* Set the frequency of the crystal */
+#if TEENSY
+ PLLCSR |= (1 << PINDIV); /* For 16MHz crystal on Teensy board */
+#else
+ PLLCSR &= ~(1 << PINDIV); /* For 8MHz crystal on TeleScience board */
+#endif
+
+ /* Enable the PLL */
+ PLLCSR |= (1 << PLLE);
+ while (!(PLLCSR & (1 << PLOCK)))
+ ;
+}
+
+static void
+timer0_init(void)
+{
+ TCCR0A = ((1 << COM0A1) |
+ (0 << COM0A0) |
+ (1 << WGM01) |
+ (1 << WGM00));
+
+ OCR0A = 0x10;
+ OCR0B = 0;
+ TIMSK0 = 0;
+
+ TCCR0B = ((0 << WGM02) |
+ (5 << CS00));
+}
+
+ISR(ADC_vect)
+{
+ OCR0A = ADCH;
+}
+
+#define ADC_CHANNEL 0x25 /* Channel ADC13 */
+#define ADC_CHANNEL_LOW(c) (((c) & 0x1f) << MUX0)
+#define ADC_CHANNEL_HIGH(c) ((((c) & 0x20) >> 5) << MUX5)
+
+#define ADCSRA_INIT ((1 << ADEN) | /* Enable ADC */ \
+ (0 << ADATE) | /* No auto ADC trigger */ \
+ (1 << ADIE) | /* Enable interrupt */ \
+ (6 << ADPS0)) /* Prescale clock by 64 */
+
+#define ADCSRB_INIT ((0 << ADHSM) | /* No high-speed mode */ \
+ (0 << ACME) | /* Some comparitor thing */ \
+ (0 << ADTS0)) /* Free running mode (don't care) */
+
+static void
+adc_start(void)
+{
+ ADMUX = ((0 << REFS1) | /* AVcc reference */
+ (1 << REFS0) | /* AVcc reference */
+ (1 << ADLAR) | /* Left-shift results */
+ (ADC_CHANNEL_LOW(ADC_CHANNEL))); /* Select channel */
+
+ ADCSRB = ADCSRB_INIT | ADC_CHANNEL_HIGH(ADC_CHANNEL);
+
+ ADCSRA = ADCSRA_INIT | (1 << ADSC); /* Start conversion */
+}
+
+static void
+adc_init(void)
+{
+ ADCSRA = ADCSRA_INIT;
+ ADCSRB = ADCSRB_INIT;
+ DIDR0 |= (1 << 0);
+}
+
+#define AO_STACK_SIZE 128
+
+uint8_t new_stack[512];
+int stack_count;
+
+#define PUSH8(stack, val) (*--(stack) = (val))
+
+#define PUSH16(stack, val) PUSH8(stack, ((uint16_t) (val))); PUSH8(stack, ((uint16_t) (val)) >> 8)
+
+void
+count(int count)
+{
+
+}
+
+void
+blink(void)
+{
+ while (1) {
+ LEDPORT ^= (1 << LEDOUT);
+ _delay_ms(200);
+ }
+}
+
+void
+function(void)
+{
+ return;
+}
+
+void
+init_stack(void (*f) (void))
+{
+ uint8_t *stack = new_stack + AO_STACK_SIZE;
+ uint8_t i;
+
+ /* Return address */
+ PUSH16(stack, f);
+
+#if 0
+ /* Clear register values */
+ i = 32;
+ while (i--)
+ PUSH8(stack, 0);
+
+ /* SREG with interrupts enabled */
+ PUSH8(stack, 0x80);
+#endif
+ stack_count = stack - new_stack;
+}
+
+void
+switch_stack(void) __attribute__((naked));
+
+void
+switch_stack(void)
+{
+#if 0
+ uint16_t a;
+ uint8_t l, h;
+
+ a = (uint16_t) function;
+ l = a;
+ h = a >> 8;
+ asm("push %0" : : "r" (l));
+ asm("push %0" : : "r" (h));
+ asm("ret");
+#endif
+#if 0
+ asm("push r31; push r30");
+ asm("push r29; push r28; push r27; push r26; push r25");
+ asm("push r24; push r23; push r22; push r21; push r20");
+ asm("push r19; push r18; push r17; push r16; push r15");
+ asm("push r14; push r13; push r12; push r11; push r10");
+ asm("push r9; push r8; push r7; push r6; push r5");
+ asm("push r4; push r3; push r2; push r1; push r0");
+ asm("in r0, __SREG__" "\n\t"
+ "push r0");
+#endif
+ uint8_t *sp = (new_stack + stack_count);
+ uint8_t sp_l, sp_h;
+
+ sp_l = (uint16_t) sp;
+ sp_h = ((uint16_t) sp) >> 8;
+ asm("out __SP_H__,%0" : : "r" (sp_h) );
+ asm("out __SP_L__,%0" : : "r" (sp_l) );
+ blink();
+#if 0
+ asm("pop r0" "\n\t"
+ "out __SREG__, r0");
+ asm("pop r0; pop r1; pop r2; pop r3; pop r4");
+ asm("pop r5; pop r6; pop r7; pop r8; pop r9");
+ asm("pop r10; pop r11; pop r12; pop r13; pop r14");
+ asm("pop r15; pop r16; pop r17; pop r18; pop r19");
+ asm("pop r20; pop r21; pop r22; pop r23; pop r24");
+ asm("pop r25; pop r26; pop r27; pop r28; pop r29");
+ asm("pop r30; pop r31");
+#endif
+ asm("ret");
+}
+
+void back(void)
+{
+ switch_stack();
+ blink();
+}
+
+void main(void)
+{
+#if 0
+ clock_init();
+ adc_init();
+ timer1_init();
+ timer0_init();
+#endif
+
+ LEDDDR |= (1 << LEDDDRPIN);
+
+ init_stack(blink);
+ switch_stack();
+}
--- /dev/null
+/*
+ * Copyright © 2011 Keith Packard <keithp@keithp.com>
+ *
+ * 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; version 2 of the License.
+ *
+ * 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, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#define TEENSY 1
+#if TEENSY
+#define F_CPU 16000000UL // 16 MHz
+#else
+#define F_CPU 8000000UL // 8 MHz
+#endif
+#include <util/delay.h>
+
+#define LEDOUT PORTB7
+#define LEDPORT PORTB
+#define LEDDDR DDRB
+#define LEDDDRPIN DD7
+
+static void
+timer1_init(void)
+{
+ TCCR1A = ((0 << WGM11) | /* CTC mode, OCR1A */
+ (0 << WGM10)); /* CTC mode, OCR1A */
+ TCCR1B = ((0 << ICNC1) | /* no input capture noise canceler */
+ (0 << ICES1) | /* input capture on falling edge (don't care) */
+ (0 << WGM13) | /* CTC mode, OCR1A */
+ (1 << WGM12) | /* CTC mode, OCR1A */
+ (3 << CS10)); /* clk/64 from prescaler */
+
+#if TEENSY
+ OCR1A = 2500; /* 16MHz clock */
+#else
+ OCR1A = 1250; /* 8MHz clock */
+#endif
+
+ TIMSK1 = (1 << OCIE1A); /* Interrupt on compare match */
+}
+
+static void
+clock_init(void)
+{
+ /* disable RC clock */
+ CLKSEL0 &= ~(1 << RCE);
+
+ /* Disable PLL */
+ PLLCSR &= ~(1 << PLLE);
+
+ /* Enable external clock */
+ CLKSEL0 |= (1 << EXTE);
+
+ /* wait for external clock to be ready */
+ while ((CLKSTA & (1 << EXTON)) == 0)
+ ;
+
+ /* select external clock */
+ CLKSEL0 |= (1 << CLKS);
+
+ /* Disable the clock prescaler */
+ cli();
+ CLKPR = (1 << CLKPCE);
+ CLKPR = 0;
+ sei();
+
+ /* Set up the PLL to use the crystal */
+
+ /* Use primary system clock as PLL source */
+ PLLFRQ = ((0 << PINMUX) | /* Use primary clock */
+ (0 << PLLUSB) | /* No divide by 2 for USB */
+ (0 << PLLTM0) | /* Disable high speed timer */
+ (0x4 << PDIV0)); /* 48MHz PLL clock */
+
+ /* Set the frequency of the crystal */
+#if TEENSY
+ PLLCSR |= (1 << PINDIV); /* For 16MHz crystal on Teensy board */
+#else
+ PLLCSR &= ~(1 << PINDIV); /* For 8MHz crystal on TeleScience board */
+#endif
+
+ /* Enable the PLL */
+ PLLCSR |= (1 << PLLE);
+ while (!(PLLCSR & (1 << PLOCK)))
+ ;
+}
+
+void
+uart_send(char data)
+{
+ while (!(UCSR1A & (1 << UDRE1)))
+ ;
+ UDR1 = data;
+}
+
+void
+uart_init(uint16_t baud)
+{
+ PRR1 &= ~(1 << PRUSART1);
+ UBRR1L = baud;
+ UBRR1H = baud >> 8;
+ UCSR1A = 0;
+ UCSR1B = ((1 << RXEN1) | /* Enable receiver */
+ (1 << TXEN1)); /* Enable transmitter */
+ UCSR1C = ((0 << UMSEL10) | /* Asynchronous mode */
+ (0 << UPM10) | /* No parity */
+ (0 << USBS1) | /* 1 stop bit */
+ (3 << UCSZ10) | /* 8 bit characters */
+ (0 << UCPOL1)); /* MBZ for async mode */
+}
+
+int main(void)
+{
+ clock_init();
+ timer1_init();
+ uart_init(832);
+
+ LEDDDR |= (1 << LEDDDRPIN);
+
+ for (;;) {
+ LEDPORT ^= (1 << LEDOUT);
+ uart_send('H');
+ }
+}
projects / fw / altos / commitdiff