From ff6e482b1ca3d0b0657baa03d4184618ededbfa4 Mon Sep 17 00:00:00 2001
From: travisutk <travisutk@12e2690d-a6be-4b82-a7b7-67c4a43b65c8>
Date: Thu, 18 Jun 2009 18:33:55 +0000
Subject: [PATCH] Forgot JTAG module, prereq for JTAG430. Here it is.

git-svn-id: https://svn.code.sf.net/p/goodfet/code/trunk@39 12e2690d-a6be-4b82-a7b7-67c4a43b65c8
---
 firmware/apps/jtag/jtag.c | 164 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)
 create mode 100644 firmware/apps/jtag/jtag.c

diff --git a/firmware/apps/jtag/jtag.c b/firmware/apps/jtag/jtag.c
new file mode 100644
index 0000000..cffec3d
--- /dev/null
+++ b/firmware/apps/jtag/jtag.c
@@ -0,0 +1,164 @@
+//GoodFET JTAG Application
+//Handles basic I/O
+
+//Higher level left to client application.
+
+#include "platform.h"
+#include "command.h"
+#include "jtag.h"
+
+
+
+
+//! Set up the pins for JTAG mode.
+unsigned char jtagsetup(){
+  P5DIR|=MOSI+SCK+TMS;
+  P5DIR&=~MISO;
+  P5OUT|=0xFFFF;
+  P4DIR|=TST;
+  P2DIR|=RST;
+}
+
+int savedtclk=0;
+//! Shift 8 bits in and out.
+unsigned char jtagtrans8(unsigned char byte){
+  unsigned int bit;
+  SAVETCLK;
+  for (bit = 0; bit < 8; bit++) {
+    /* write MOSI on trailing edge of previous clock */
+    if (byte & 0x80)
+      SETMOSI;
+    else
+      CLRMOSI;
+    byte <<= 1;
+    
+    if(bit==7)
+      SETTMS;//TMS high on last bit to exit.
+    
+    CLRTCK;
+    SETTCK;
+     /* read MISO on trailing edge */
+    byte |= READMISO;
+  }
+  RESTORETCLK;
+  
+  // exit state
+  CLRTCK;
+  SETTCK;
+  // update state
+  CLRTMS;
+  CLRTCK;
+  SETTCK;
+  
+  return byte;
+}
+
+//! Shift 8 bits in and out.
+unsigned int jtagtrans16(unsigned int word){
+  unsigned int bit;
+  SAVETCLK;
+  
+  for (bit = 0; bit < 16; bit++) {
+    /* write MOSI on trailing edge of previous clock */
+    if (word & 0x8000)
+      SETMOSI;
+    else
+      CLRMOSI;
+    word <<= 1;
+    
+    if(bit==15)
+      SETTMS;//TMS high on last bit to exit.
+    
+    CLRTCK;
+    SETTCK;
+     /* read MISO on trailing edge */
+    word |= READMISO;
+  }
+  RESTORETCLK;
+  
+  // exit state
+  CLRTCK;
+  SETTCK;
+  // update state
+  CLRTMS;
+  CLRTCK;
+  SETTCK;
+  
+  return word;
+}
+
+//! Stop JTAG, release pins
+void jtag_stop(){
+  P5OUT=0;
+  P4OUT=0;
+}
+
+
+//! Shift 16 bits of the DR.
+unsigned int jtag_dr_shift16(unsigned int in){
+  // idle
+  SETTMS;
+  CLRTCK;
+  SETTCK;
+  // select DR
+  CLRTMS;
+  CLRTCK;
+  SETTCK;
+  // capture IR
+  CLRTCK;
+  SETTCK;
+
+  // shift DR, then idle
+  return(jtagtrans16(in));
+}
+
+
+//! Shift 8 bits of the IR.
+unsigned char jtag_ir_shift8(unsigned char in){
+  // idle
+  SETTMS;
+  CLRTCK;
+  SETTCK;
+  // select DR
+  CLRTCK;
+  SETTCK;
+  // select IR
+  CLRTMS;
+  CLRTCK;
+  SETTCK;
+  // capture IR
+  CLRTCK;
+  SETTCK;
+  
+  // shift IR, then idle.
+  return(jtagtrans8(in));
+}
+
+//! Handles a monitor command.
+void jtaghandle(unsigned char app,
+	       unsigned char verb,
+	       unsigned char len){
+  switch(verb){
+    //START handled by specific JTAG
+  case STOP:
+    jtag_stop();
+    txdata(app,verb,0);
+    break;
+  case SETUP:
+    jtagsetup();
+    txdata(app,verb,0);
+    break;
+  case JTAG_IR_SHIFT:
+    cmddata[0]=jtag_ir_shift8(cmddata[0]);
+    txdata(app,verb,1);
+    break;
+  case JTAG_DR_SHIFT:
+    cmddataword[0]=jtag_dr_shift16(cmddataword[0]);
+    txdata(app,verb,2);
+    break;
+  default:
+    txdata(app,NOK,0);
+  }
+}
+
+
-- 
2.20.1