Works: measures time and client displays a primitive stripchart.

3 files changed, 118 insertions, 143 deletions

diff --git a/example.c b/example.c
index 129b6eb..7409fdf 100644
--- a/example.c
+++ b/example.c
@@ -36,38 +36,55 @@ 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);
 
-// Very simple character echo test
 int main(void)
 {
-	int changed = 0;
+	int changed = 0, val;
 	int port = 'B' - 'A';
-	int pin = '0' - '0';
-	int val;
-	CPU_PRESCALE(0);
+	int pin = 1 << ('0' - '0');
+	int latency = 0;
+
+	CPU_PRESCALE(0x00); // 16 MHz
 	usb_init();
 	LED_CONFIG;
 	while (!usb_configured()) /* wait */ ;
 	_delay_ms(1000);
-
-	LED_ON;
-
+	CPU_PRESCALE(0x04); // 1 MHz
 
 	uint8_t *portload = 0x20 + port * 3;
+	*portload &= ~pin;
 
-	*(uint8_t *)(0x21 + port * 3) &= ~(1 << pin);
-
+	TCCR1B |= (1 << CS10); // Set timer1 to 1 microsecond steps
 
 	while (1) {
-		val = *portload & (1 << pin);
-//		usb_serial_putchar(val + '0');
-		if ((val == 1)  && (changed == 0)) {
-			changed = 1;
-			usb_serial_putchar(val ? '1' : '0');
-			LED_ON;
-		} else if ((val == 0)  && (changed == 1)) {
+		val = *portload & pin;
+		if ((val == 0)  && (changed == 1)) {
+			/* trailing edge of pulse.
+			 *
+			 * I track the 1->0 transition rather than
+			 * 0->1 because it's sharper.
+			 */
+			int count;
+			count = TCNT1; // read timer
+			if (count < 15000)
+				/* ignore spurious pulses.  If I don't
+				 * do this, for some reason I'll see a
+				 * bunch of half-width pulses.
+				 */
+				continue;
+			TCNT1 = 0; // reset timer
 			changed = 0;
-			usb_serial_putchar(val ? '1' : '0');
-			LED_OFF;
+
+//			usb_serial_putchar(count > 16667 ? '>' : '<');
+			send_int(count);
+			usb_serial_putchar(' ');
+			send_int(latency);
+			usb_serial_putchar('\n');
+			latency = TCNT1;
+		} else if ((val == 1)  && (changed == 0)) {
+			/* leading edge of pulse.
+			 */
+			changed = 1;
+//			usb_serial_putchar('0');
 		}
 	}
 }
@@ -85,6 +102,23 @@ void send_str(const char *s)
 	}
 }
 
+/* Write a decimal integer to the serial port
+ */
+void send_int(int val)
+{
+	char c_out[10];
+	int ptr;
+	c_out[ptr++] = '\0';
+	while (val > 0) {
+		c_out[ptr++] = (val % 10) + '0';
+		val /= 10;
+	}
+	ptr--;
+	while (ptr) {
+		usb_serial_putchar(c_out[ptr--]);
+	}
+}
+
 // Receive a string from the USB serial port.  The string is stored
 // in the buffer and this function will not exceed the buffer size.
 // A carriage return or newline completes the string, and is not
diff --git a/host/client.c b/host/client.c
new file mode 100644
index 0000000..29a2455
--- /dev/null
+++ b/host/client.c
@@ -0,0 +1,65 @@
+/* Thinger to read 60hz cycle times and display diagnostics in a kind
+ * of stripcharty way.
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <fcntl.h>
+
+#define QUEUE 100
+#define WIDTH 40
+
+int main(int *argc, char **argv)
+{
+	char line[WIDTH + 10];
+	double bottom = 1000000/59.9;
+	double top = 1000000/60.1;
+	double center = 1000000/60;
+	double queue[QUEUE];
+	int counter;
+	int qpos = 0;
+	int fd = open("/dev/ttyACM0", O_RDONLY);
+
+	while (1) {
+		double current, average;
+		char line[] = "                    |                    ";
+		char inlin[20];
+		int position, pos_avg, i;
+		int len = read(fd, &inlin, 20);
+		if (len == 0) {
+			puts("Fucked\n");
+			continue;
+		}
+		current = (double)atoi(&inlin);
+		queue[qpos++] = current;
+		counter++;
+		if (qpos == QUEUE)
+			qpos = 0;
+
+		average = 0;
+		for (i = 0; i < QUEUE; i++) {
+			average += queue[i];
+		}
+		average /= QUEUE;
+		pos_avg = WIDTH-(int)((top-average)/((top-bottom)/WIDTH));
+		position = WIDTH-(int)((top-current)/((top-bottom)/WIDTH));
+
+		if (position > WIDTH) {
+			line[WIDTH] = '>';
+		} else if (position < 0) {
+			line[0] = '<';
+		} else {
+			line[position] = '.';
+		}
+
+		if (pos_avg > WIDTH) {
+			line[WIDTH] = '_';
+		} else if (pos_avg < 0) {
+			line[0] = '_';
+		} else {
+			line[pos_avg] = '*';
+		}
+		if (counter % 15 == 0)
+			printf("[%s] %f\n", line, 1/(average/1000000));
+	}
+}
diff --git a/main.c b/main.c
deleted file mode 100644
index 9e090ba..0000000
--- a/main.c
+++ /dev/null
@@ -1,124 +0,0 @@
-/* Keyboard example for Teensy USB Development Board
- * http://www.pjrc.com/teensy/usb_keyboard.html
- * Copyright (c) 2008 PJRC.COM, LLC
- * 
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- * 
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- * 
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-#include <avr/io.h>
-#include <avr/pgmspace.h>
-#include <avr/interrupt.h>
-#include <util/delay.h>
-#include "usb_keyboard.h"
-
-#define LED_CONFIG	(DDRD |= (1<<6))
-#define LED_ON		(PORTD &= ~(1<<6))
-#define LED_OFF		(PORTD |= (1<<6))
-#define CPU_PRESCALE(n)	(CLKPR = 0x80, CLKPR = (n))
-
-uint8_t number_keys[10]=
-	{KEY_0,KEY_1,KEY_2,KEY_3,KEY_4,KEY_5,KEY_6,KEY_7,KEY_8,KEY_9};
-
-uint16_t idle_count=0;
-
-int main(void)
-{
-	uint8_t b, d, mask, i, reset_idle;
-	uint8_t b_prev=0xFF, d_prev=0xFF;
-
-	// set for 16 MHz clock
-	CPU_PRESCALE(0);
-
-	// Configure all port B and port D pins as inputs with pullup resistors.
-	// See the "Using I/O Pins" page for details.
-	// http://www.pjrc.com/teensy/pins.html
-	DDRD = 0x00;
-	DDRB = 0x00;
-	PORTB = 0xFF;
-	PORTD = 0xFF;
-
-	// 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 */ ;
-
-	// Wait an extra second for the PC's operating system to load drivers
-	// and do whatever it does to actually be ready for input
-	_delay_ms(1000);
-
-	// Configure timer 0 to generate a timer overflow interrupt every
-	// 256*1024 clock cycles, or approx 61 Hz when using 16 MHz clock
-	// This demonstrates how to use interrupts to implement a simple
-	// inactivity timeout.
-	TCCR0A = 0x00;
-	TCCR0B = 0x05;
-	TIMSK0 = (1<<TOIE0);
-
-	while (1) {
-		// read all port B and port D pins
-		b = PINB;
-		d = PIND;
-		// check if any pins are low, but were high previously
-		mask = 1;
-		reset_idle = 0;
-		for (i=0; i<8; i++) {
-			if (((b & mask) == 0) && (b_prev & mask) != 0) {
-				usb_keyboard_press(KEY_B, KEY_SHIFT);
-				usb_keyboard_press(number_keys[i], 0);
-				reset_idle = 1;
-			}
-			if (((d & mask) == 0) && (d_prev & mask) != 0) {
-				usb_keyboard_press(KEY_D, KEY_SHIFT);
-				usb_keyboard_press(number_keys[i], 0);
-				reset_idle = 1;
-			}
-			mask = mask << 1;
-		}
-		// if any keypresses were detected, reset the idle counter
-		if (reset_idle) {
-			// variables shared with interrupt routines must be
-			// accessed carefully so the interrupt routine doesn't
-			// try to use the variable in the middle of our access
-			cli();
-			idle_count = 0;
-			sei();
-		}
-		// now the current pins will be the previous, and
-		// wait a short delay so we're not highly sensitive
-		// to mechanical "bounce".
-		b_prev = b;
-		d_prev = d;
-		_delay_ms(2);
-	}
-}
-
-// This interrupt routine is run approx 61 times per second.
-// A very simple inactivity timeout is implemented, where we
-// will send a space character.
-ISR(TIMER0_OVF_vect)
-{
-	idle_count++;
-	if (idle_count > 61 * 8) {
-		idle_count = 0;
-		usb_keyboard_press(KEY_SPACE, 0);
-	}
-}
-
-