AVR support getting better.

[goodfet] / firmware / apps / avr / avr.c

diff --git a/firmware/apps/avr/avr.c b/firmware/apps/avr/avr.c
index 47ae68e..707ab9e 100644 (file)
--- a/firmware/apps/avr/avr.c
+++ b/firmware/apps/avr/avr.c
@@ -19,44 +19,71 @@ void avrsetup(){
 
 //! Initialized an attached AVR.
 void avrconnect(){
-  register int i;
-  avrsetup();//set I/O pins
+  //set I/O pins
+  avrsetup();
   
   //Pulse !RST (SS) at least twice while CLK is low.
+  CLRCLK;
   CLRSS;
+
+  SETSS;
   CLRCLK;
-  
-  for(i=0;i<5;i++){
-    SETSS;
-    CLRSS;
-  }
+  delay(500);
+  CLRSS;
+  delay(500);
   
   //Enable programming
   avr_prgen();
 }
 
+//! Read and write an SPI byte with delays.
+unsigned char avrtrans8(unsigned char byte){
+  register unsigned int bit;
+  //This function came from the SPI Wikipedia article.
+  //Minor alterations.
+  
+  for (bit = 0; bit < 8; bit++) {
+    /* write MOSI on trailing edge of previous clock */
+    if (byte & 0x80)
+      SETMOSI;
+    else
+      CLRMOSI;
+    byte <<= 1;
+    
+    delay(2);
+    SETCLK;
+  
+    /* read MISO on trailing edge */
+    byte |= READMISO;
+    delay(2);
+    CLRCLK;
+  }
+  
+  return byte;
+}
+
 //! Perform a 4-byte exchange.
 u8 avrexchange(u8 a, u8 b, u8 c, u8 d){
-  spitrans8(a);
-  spitrans8(b);
-  if(spitrans8(c)!=b){
+  avrtrans8(a);
+  avrtrans8(b);
+  if(avrtrans8(c)!=b){
     debugstr("AVR sync error, b not returned as c.");
+    //Reconnect here?
   }
-  spitrans8(c);
-  return spitrans8(d);
+  return avrtrans8(d);
 }
 
 //! Enable AVR programming mode.
 void avr_prgen(){
-  avrexchange(0xac, 0x53, 0, 0);
+  avrexchange(0xAC, 0x53, 0, 0);
 }
 
 //! Read AVR device code.
-u8 avr_devicecode(){
+u8 avr_sig(u8 i){
   return avrexchange(0x30, //Read signature byte
              0x00,
-             0x00, //&0x03 is sig adr
-             0x00 //don't care.
+             i&0x03,      //sig adr
+             0x00         //don't care.
              );
 }
 
@@ -78,9 +105,13 @@ void avrhandle(unsigned char app,
     avrsetup();
     txdata(app,verb,0);
     break;
-  case START:
+  case START://returns device code
     avrconnect();
-    txdata(app,verb,0);
+    //no break here
+  case AVR_PEEKSIG:
+    for(i=0;i<4;i++)
+      cmddata[i]=avr_sig(i);
+    txdata(app,verb,4);
     break;
   case PEEK:
   case POKE: