update for I2C

HamShield.cpp

@@ -119,28 +119,24 @@ volatile long bouncer = 0;
  * @see A1846S_DEFAULT_ADDRESS
  */
 HamShield::HamShield() {
-    devAddr = A1; // devAddr is the chip select pin used by the HamShield
+    devAddr = A1846S_DEV_ADDR_SENLOW;
     sHamShield = this;
 	
     pinMode(A1, OUTPUT);
-    digitalWrite(A1, HIGH);
-    pinMode(A4, OUTPUT);
-    pinMode(A5, OUTPUT);
+    digitalWrite(A1, LOW);
 }
 
 /** Specific address constructor.
- * @param chip select pin for HamShield
+ * @param address the I2C address of the HamShield
  * @see A1846S_DEFAULT_ADDRESS
  * @see A1846S_ADDRESS_AD0_LOW
  * @see A1846S_ADDRESS_AD0_HIGH
  */
-HamShield::HamShield(uint8_t cs_pin) {
-    devAddr = cs_pin;
+HamShield::HamShield(uint8_t address) {
+    devAddr = address;
 
-	pinMode(A1, OUTPUT);
-    digitalWrite(A1, HIGH);
-    pinMode(A4, OUTPUT);
-    pinMode(A5, OUTPUT);
+    pinMode(A1, OUTPUT);
+    digitalWrite(A1, LOW);
 }
 
 /** Power on and prepare for general usage.

HamShield.h

@@ -263,7 +263,7 @@ class HamShield {
         static HamShield *sHamShield; // HamShield singleton, used for ISRs mostly
 		
         HamShield();
-        HamShield(uint8_t cs_pin);
+        HamShield(uint8_t address);
 
         void initialize();
         bool testConnection();

HamShield_comms.cpp

@@ -1,5 +1,5 @@
 /*
- * Based loosely on I2Cdev by Jeff Rowberg, except for all kludgy bit-banging
+ * Based loosely on I2Cdev by Jeff Rowberg
  */
 
 #include "HamShield_comms.h"
@@ -27,61 +27,36 @@ int8_t HSreadBitsW(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t l
 
 int8_t HSreadWord(uint8_t devAddr, uint8_t regAddr, uint16_t *data)
 {
-	//return I2Cdev::readWord(devAddr, regAddr, data);
 
-	uint8_t temp;
-	uint16_t temp_dat;
-	// bitbang for great justice!
-	*data = 0;
-	cli();
-	DDRC |= ((1<<5) | (1<<4)); // set direction to output
-	sei();
-	regAddr = regAddr | (1 << 7);
+    int8_t count = 0;
+    uint32_t t1 = millis();
+	uint8_t timeout = 1000;
 
-	//cli();
-	digitalWrite(devAddr, 0); //PORTC &= ~(1<<1); //devAddr used as chip select
-	//sei();
-	for (int i = 0; i < 8; i++) {
-		temp = ((regAddr & (0x80 >> i)) != 0);
-		cli();
-		PORTC &= ~(1<<5); //digitalWrite(CLK, 0);
-		sei();
-		//digitalWrite(DAT, regAddr & (0x80 >> i));
-		temp = (PORTC & ~(1<<4)) + (temp << 4);
-		cli();
-		PORTC = temp;
-		sei();
-		delayMicroseconds(9);
-		cli();
-		PORTC |= (1<<5); //digitalWrite(CLK, 1);
-		sei();
-		delayMicroseconds(9);
-	}
-	// change direction of DAT
-	cli();
-	DDRC &= ~(1<<4); //pinMode(DAT, INPUT);
-	sei();
-	for (int i = 15; i >= 0; i--) {
-		cli();
-		PORTC &= ~(1<<5); //digitalWrite(CLK, 0);
-		sei();
-		delayMicroseconds(9);
-		cli();
-		PORTC |= (1<<5); //digitalWrite(CLK, 1);
-		sei();
-		cli();
-		temp_dat = ((PINC & (1<<4)) != 0);
-		sei();
-		temp_dat = temp_dat << i;
-		*data |= temp_dat; // digitalRead(DAT);
-		delayMicroseconds(9);
-	}
-	digitalWrite(devAddr, 1); //PORTC |= (1<<1);// CS
+	Wire.beginTransmission(devAddr);
+    Wire.write(regAddr);
+    Wire.endTransmission(false);
+//                Wire.beginTransmission(devAddr);
+    Wire.requestFrom((int)devAddr, 2); // length=words, this wants bytes
+        
+    bool msb = true; // starts with MSB, then LSB
+    for (; Wire.available() && count < 1 && (timeout == 0 || millis() - t1 < timeout);) {
+        if (msb) {
+            // first byte is bits 15-8 (MSb=15)
+            data[0] = Wire.read() << 8;
+        } else {
+            // second byte is bits 7-0 (LSb=0)
+            data[0] |= Wire.read();
+            count++;
+        }
+        msb = !msb;
+    }
+        
+    Wire.endTransmission();
+
+    if (timeout > 0 && millis() - t1 >= timeout && count < 1) count = -1; // timeout
+    
+    return count;
 
-	cli();	
-	DDRC &= ~((1<<5) | (1<<4)); // set direction all input (for ADC)
-	sei();
-	return 1;
 }
 
 
@@ -95,7 +70,7 @@ bool HSwriteBitW(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint16_t data
 
 bool HSwriteBitsW(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint16_t data)
 {
-uint16_t w;
+	uint16_t w;
     if (HSreadWord(devAddr, regAddr, &w) != 0) {
         uint16_t mask = ((1 << length) - 1) << (bitStart - length + 1);
         data <<= (bitStart - length + 1); // shift data into correct position
@@ -110,60 +85,14 @@ uint16_t w;
 
 bool HSwriteWord(uint8_t devAddr, uint8_t regAddr, uint16_t data)
 {
-	//return I2Cdev::writeWord(devAddr, regAddr, data);
+    uint8_t status = 0;
 
-	uint8_t temp_reg;
-	uint16_t temp_dat;
+	Wire.beginTransmission(devAddr);
+        Wire.write(regAddr); // send address
 
-	//digitalWrite(13, HIGH);
+            Wire.write((uint8_t)(data >> 8));    // send MSB
+            Wire.write((uint8_t)data);         // send LSB
   
-	// bitbang for great justice!
-	cli();
-	DDRC |= ((1<<5) | (1<<4)); // set direction all output
-	//PORTC |= (1<<5) & (1<<4);
-	sei();
-	regAddr = regAddr & ~(1 << 7);
-	
-	//cli();
-	digitalWrite(devAddr, 0); // PORTC &= ~(1<<1); //CS
-	//sei();
-	for (int i = 0; i < 8; i++) {
-		temp_reg = ((regAddr & (0x80 >> i)) != 0);
-		cli();
-		PORTC &= ~(1<<5); //digitalWrite(CLK, 0);
-		sei();
-		//digitalWrite(DAT, regAddr & (0x80 >> i));
-		temp_reg = (PORTC & ~(1<<4)) + (temp_reg << 4);
-		cli();
-		PORTC = temp_reg;
-		sei();
-		delayMicroseconds(8);
-		cli();
-		PORTC |= (1<<5); //digitalWrite(CLK, 1);
-		sei();
-		delayMicroseconds(10);
-	}
-	for (int i = 0; i < 16; i++) {
-		temp_dat = ((data & (0x8000 >> i)) != 0);
-		cli();
-		PORTC &= ~(1<<5); //digitalWrite(CLK, 0);
-		sei();
-		//digitalWrite(DAT, data & (0x80000 >> i));
-		temp_reg = (PORTC & ~(1<<4)) + (temp_dat << 4);
-		cli();
-		PORTC = temp_reg;
-		sei();
-		delayMicroseconds(7);
-		cli();
-		PORTC |= (1<<5); //digitalWrite(CLK, 1);
-		sei();
-		delayMicroseconds(10);
-	}
-	
-	digitalWrite(devAddr, 1); //PORTC |= (1<<1); //CS
-	
-	cli();
-	DDRC &= ~((1<<5) | (1<<4)); // set direction to input for ADC
-	sei();
-	return true;
+        status = Wire.endTransmission();
+    return status == 0;
 }

HamShield_comms.h

@@ -5,11 +5,7 @@
 #define _HAMSHIELD_COMMS_H_
 
 #include "Arduino.h"
-//#include "I2Cdev.h"
-
-#define nSEN A1
-#define CLK A5
-#define DAT A4
+#include "Wire.h"
 
 int8_t HSreadBitW(uint8_t devAddr, uint8_t regAddr, uint8_t bitNum, uint16_t *data);
 int8_t HSreadBitsW(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint16_t *data);

README.md

@@ -1,6 +1,16 @@
 # HamShield
 
-The master branch is intended for use with HamShield hardware -09 and above.
+The i2c-comms branch is not intended for use with a stock HamShield.
+
+To use i2c communications with a HamShield 09 or above, you must first make several hardware changes to the board.
+
+1. Remove R2
+2. Short the pads of R17 (either with a wire or a low value resistor).
+
+Then make sure that you pull the nCS pin correctly. Changing nCS changes the I2C address of the HamShield:
+
+- nCS is logic high: A1846S_DEV_ADDR_SENHIGH 0b0101110
+- nCS is logic low: A1846S_DEV_ADDR_SENLOW  0b1110001
 
 HamShield Arduino Library and Example Sketches