fix support for ADNS-5050 optical sensor

README

@@ -66,7 +66,7 @@ Wiring:
                  .--v--.
                 -|     |- VCC
           GPS <--|  T  |--> I²C SCL
-                -|  i  |-
+                -|  i  |--> Optical CSEL
   Optical DIO <--|  n  |--> I²C SDA
   Optical CLK <--|  y  |-
 Sonar Trigger <--|  4  |-

config.h

@@ -12,8 +12,8 @@
 #define USE_SONAR 1
 /* query optical flow sensor?
  *
- * The optical flow sensor (A5050) must be connected to PA0 (SCK) and PA1
- * (SDIO) pins.
+ * The optical flow sensor (A5050) must be connected to PA0 (SCK), PA1 (SDIO)
+ * and PB6 (CSEL/NCS) pins.
  */
 #define USE_OPTICAL 1
 

optical.c

@@ -8,80 +8,110 @@
 #include <util/delay.h>
 #include "optical.h"
 
+#if __AVR__
+#include <util/atomic.h>
+#define ATOMIC(t) ATOMIC_BLOCK(t)
+#else
+#define ATOMIC(t)
+#endif
+
 #define OPTICAL_SCLK_PORT PORTA
 #define OPTICAL_SDIO_PORT PORTA
+#define OPTICAL_CSEL_PORT PORTB
 #define OPTICAL_SCLK_DDR  DDRA
 #define OPTICAL_SDIO_DDR  DDRA
+#define OPTICAL_CSEL_DDR  DDRB
 #define OPTICAL_SCLK_PIN  PINA
 #define OPTICAL_SDIO_PIN  PINA
+#define OPTICAL_CSEL_PIN  PINB
 #define OPTICAL_SCLK_BIT  PA0
 #define OPTICAL_SDIO_BIT  PA1
+#define OPTICAL_CSEL_BIT  PB6
 
 #define IO_DELAY   4
 
+/* values for ADNS 5050 */
 #define ID_REG     0x00
 #define MOTION_REG 0x02
 #define DX_REG     0x03
 #define DY_REG     0x04
 #define QUAL_REG   0x05
 #define RESET_REG  0x3a
+#define RESET_VAL  0x5a
 #define CTRL1_REG  0x0d
 #define CTRL2_REG  0x19
 
 static void _spi_write(uint8_t d) {
 	OPTICAL_SDIO_DDR |= 1<<OPTICAL_SDIO_BIT;
-	for (uint8_t i=0; i<8; i++) {
-		OPTICAL_SCLK_PORT &= ~(1<<OPTICAL_SDIO_BIT);
+	for (int8_t i=7; i>=0; i--) {
+		OPTICAL_SCLK_PORT &= ~(1<<OPTICAL_SCLK_BIT);
+		_delay_us(1);
 		if (d & 1<<i) {
 			OPTICAL_SDIO_PORT |= 1<<OPTICAL_SDIO_BIT;
 		} else {
 			OPTICAL_SDIO_PORT &= ~(1<<OPTICAL_SDIO_BIT);
 		}
 		_delay_us(1);
-		OPTICAL_SCLK_PORT |= 1<<OPTICAL_SDIO_BIT;
+		OPTICAL_SCLK_PORT |= 1<<OPTICAL_SCLK_BIT;
+		_delay_us(1);
 	}
 }
 
 static uint8_t optical_read(uint8_t addr) {
+	OPTICAL_CSEL_PORT &= ~(1<<OPTICAL_CSEL_BIT);
 	_spi_write(addr);
-	_delay_us(IO_DELAY);
 	OPTICAL_SDIO_DDR &= ~(1<<OPTICAL_SDIO_BIT);
+	_delay_us(IO_DELAY);
 	uint8_t res = 0;
-	for (uint8_t i=0; i<8; i++) {
-		OPTICAL_SCLK_PORT &= ~(1<<OPTICAL_SDIO_BIT);
+	for (int8_t i=7; i>=0; i--) {
+		OPTICAL_SCLK_PORT &= ~(1<<OPTICAL_SCLK_BIT);
+		_delay_us(1);
+		OPTICAL_SCLK_PORT |= 1<<OPTICAL_SCLK_BIT;
 		_delay_us(1);
-		OPTICAL_SCLK_PORT |= 1<<OPTICAL_SDIO_BIT;
 		if (OPTICAL_SDIO_PIN & 1<<OPTICAL_SDIO_BIT) {
 			res |= 1<<i;
 		}
 	}
+	OPTICAL_CSEL_PORT |= (1<<OPTICAL_CSEL_BIT);
 	return res;
 }
 
 static void optical_write(uint8_t addr, uint8_t data) {
-	_spi_write(addr);
+	OPTICAL_CSEL_PORT &= ~(1<<OPTICAL_CSEL_BIT);
+	_delay_us(IO_DELAY);
+	_spi_write(addr | 1<<7);
+	_delay_us(IO_DELAY);
 	_spi_write(data);
+	_delay_us(IO_DELAY);
+	OPTICAL_CSEL_PORT |= 1<<OPTICAL_CSEL_BIT;
 }
 
 void optical_init(void) {
 	OPTICAL_SCLK_DDR |= 1<<OPTICAL_SCLK_BIT;
-	OPTICAL_SDIO_DDR |= 1<<OPTICAL_SDIO_BIT;
+	OPTICAL_SDIO_DDR &= ~(1<<OPTICAL_SDIO_BIT);
+	OPTICAL_CSEL_DDR |= 1<<OPTICAL_CSEL_BIT;
 
-	optical_write(RESET_REG, 0x5a);
-	_delay_us(50);
+	// toggle chip select to reset sensor
+	OPTICAL_CSEL_PORT |= 1<<OPTICAL_CSEL_BIT;
+	_delay_us(100);
+	OPTICAL_CSEL_PORT &= ~(1<<OPTICAL_CSEL_BIT);
+
+	// raise CLK
+	OPTICAL_SCLK_PORT |= 1<<OPTICAL_SDIO_BIT;
+	_delay_us(100);
 
-	// start motion detection and reset buffers
-	optical_write(MOTION_REG, 1);
+	optical_write(RESET_REG, RESET_VAL);
+	_delay_us(50);
 }
 
 void optical_query(struct optical_data_t *output) {
-	int8_t dx;
-	int8_t dy;
 	if (optical_read(MOTION_REG)) {
-		dx = optical_read(DX_REG);
-		dy = optical_read(DY_REG);
-		output->dx += dx;
-		output->dy += dy;
+		int8_t dy = optical_read(DY_REG);
+		int8_t dx = optical_read(DX_REG);
+		ATOMIC(ATOMIC_FORCEON) {
+			output->dx += dx;
+			output->dy += dy;
+		}
 	}
 }
 #endif

optical_structs.h

@@ -1,4 +1,4 @@
 struct optical_data_t {
-	int16_t dx;
-	int16_t dy;
+	int8_t dx;
+	int8_t dy;
 };

tiny-gps.c

@@ -27,7 +27,7 @@ struct nav_data_t nav_data = {{0}};
 #if USE_OPTICAL
 static void window_trap(void) {
 	/* did we read the last byte of the data? then reset the counters! */
-	memset(&nav_data.optical, 0, sizeof(&nav_data.optical));
+	memset(&nav_data.optical, 0, sizeof(nav_data.optical));
 }
 #define TRAP_ADDR &window_trap
 #else
@@ -50,6 +50,9 @@ int main(void) {
 #if USE_SONAR
 	sonar_init();
 #endif
+#if USE_OPTICAL
+	optical_init();
+#endif
 
 	usiTwiSlaveInit(TWIADDRESS);
 	usiTwiSetTransmitWindow( &nav_data, sizeof(nav_data) );