Changeset 137

Timestamp:

02/08/08 22:38:57 (11 months ago)

Author:

mlalondesvn

Message:

MODIF - More comments

Files:

• HDQ/hdq.cpp (modified) (5 diffs)

HDQ/hdq.cpp

@@ -1 +1 @@
 extern "C" {
-    #include <avr/pgmspace.h>
-    #include <avr/interrupt.h>
-    #include <stdio.h>
-    #include <string.h>
-    #include <inttypes.h>
-    #include <stdlib.h>
-
-    #include "wiring_private.h"
-    #include "wiring.h"
     #include "WConstants.h"
-    #include <HardwareSerial.h>
-    
     #include "pins_arduino.h"
 }
@@ -20 +9 @@
 #define _HDQ_readPin() (*inputReg & bitmask)>>pin /* Change me to inline!*/
 
+/**
+ * Constructor
+ * @param pin: pin number to attach to
+**/
 HDQ::HDQ(uint8_t pinArg)
 {
@@ -30 +23 @@
 }
 
+/**
+ * sendBreak: writes a break to the HDQ line
+**/
 void HDQ::doBreak(void)
 {
-    sbi(*modeReg, pin); // Set pin as output
+    sbi(*modeReg, pin);     // Set pin as output
+    
+    // Singal a break on the line
     cbi(*outputReg, pin);   // Bring pin low
-    
-    // Wait the minimum break time
     delayMicroseconds(HDQ_DELAY_TB);
     
-    sbi(*outputReg, pin);   // Bring the pin high again
-    
-    // Wait the minimum break time
+    // Make sure we leave enough time for the slave to recover
+    cbi(*modeReg, pin);     // Release pin
     delayMicroseconds(HDQ_DELAY_TBR);
 }
 
+/**
+ * writeByte: write a raw byte of data to the bus
+ * @param payload: the byte to send
+ * 
+**/
 void HDQ::writeByte(uint8_t payload)
 {
+    sbi(*modeReg, pin);     // Set pin as output
     
     for (uint8_t ii = 0; ii < 8; ii++)
     {
-        sbi(*modeReg, pin); // Set pin as output
-        cbi(*outputReg, pin); // Bring pin low
-        // Wait the minimum break time
+        // Start bit
+        cbi(*outputReg, pin);   // Bring pin low
         delayMicroseconds(HDQ_DELAY_BIT_START);
-    
+        
         // Toggle the pin for this bit, LSB first
         if (payload>>ii & 0x01) {
-            sbi(*outputReg, pin);
+            sbi(*outputReg, pin); // High
         }
         else {
-            cbi(*outputReg, pin);
+            cbi(*outputReg, pin); // Low
         }
-    
+        
+        // Bit time
         delayMicroseconds(HDQ_DELAY_BIT_WRITE);
-    
-        sbi(*outputReg, pin);
-
+        
+        // Stop bit
+        sbi(*outputReg, pin);   // Bring the pin high
         delayMicroseconds(HDQ_DELAY_BIT_END);
     }
@@ -72 +73 @@
 }
 
+/**
+ * write: send a payload to the device
+ * @param reg: the address of the register to write to
+ * @param payload: data to be sent
+ * @return: false, unless if verif is set, then 
+ *          it will read back the register and 
+ *          return true if it matches the payload
+**/
+boolean HDQ::write(uint8_t reg, uint8_t payload)
+{
+    // Singal a break
+    HDQ::doBreak();
+    
+    // Write the register to write
+    HDQ::writeByte((reg |= HDQ_ADDR_MASK_WRITE));
+    
+    // Wait for the slave to finish reading the register
+    delayMicroseconds((HDQ_DELAY_TRSPS_MAX - HDQ_DELAY_BIT_TOTAL) / 2);
+    
+    // Write the payload
+    HDQ::writeByte(payload);
+    
+    // Wait for the slave to finish writing the payload
+    delayMicroseconds((HDQ_DELAY_TRSPS_MAX - HDQ_DELAY_BIT_TOTAL) / 2);
+    
+    cbi(*modeReg, pin);     // Release pin
+    
+    return true;
+}
+
+/**
+ * Write with verification
+**/
 boolean HDQ::write(uint8_t reg, uint8_t payload, boolean verif)
 {
+    // Write the payload
     HDQ::write(reg, payload);
-    
+
+    // Verify the write
     if (payload == HDQ::read(reg)) return true;
-    
+
     return false;
 }
 
-boolean HDQ::write(uint8_t reg, uint8_t payload)
-{
-    HDQ::doBreak();
-    
-    HDQ::writeByte((reg |= HDQ_ADDR_MASK_WRITE));
-    
-    delayMicroseconds((HDQ_DELAY_TRSPS_MAX - HDQ_DELAY_BIT_TOTAL) / 2);
-    
-    HDQ::writeByte(payload);
-    
-    return false;
-}
 
+/**
+ * read: read from the device
+ * @param register: address of the register to read
+ * @return a uint8_t integer
+**/
 uint8_t HDQ::read(uint8_t reg)
 {
@@ -100 +129 @@
     uint8_t ii;
     
+    // Singal a break
     HDQ::doBreak();
     
+    // Write the register to read
     HDQ::writeByte((reg |= HDQ_ADDR_MASK_READ));
     
     for (ii = 0; ii < 8; ii++)
     {
-        // Wait for the slave to toggle a low
+        // Wait for the slave to toggle a low, or fail
         maxTries = HDQ_DELAY_FAIL_TRIES;
         while (_HDQ_readPin() != 0 && maxTries-- > 0)
             if (maxTries == 1) return 0xFF;
         
-        delayMicroseconds(HDQ_DELAY_BIT_WRITE / 2 + HDQ_DELAY_BIT_START); // 100 / 2 + 30
+        // Wait until Tdsub and half or one bit has passed
+        delayMicroseconds(HDQ_DELAY_BIT_WRITE / 2 + HDQ_DELAY_BIT_START);
         
+        // Read the bit
         result |= _HDQ_readPin()<<ii;
         
-        delayMicroseconds(HDQ_DELAY_TSSUB - (HDQ_DELAY_BIT_WRITE / 2 + HDQ_DELAY_BIT_START) + 10); // pass Tssub
+        // Wait until Tssub has passed
+        delayMicroseconds(HDQ_DELAY_TSSUB - (HDQ_DELAY_BIT_WRITE / 2 + HDQ_DELAY_BIT_START) + 10);
         
-        // Wait for the slave to toggle a high again
+        // Wait for the slave to toggle a high, or fail
         maxTries = HDQ_DELAY_FAIL_TRIES;
         while (_HDQ_readPin() != 1 && maxTries-- > 0)
             if (maxTries == 1) return 0xFF;
-        
     }