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--- 20b:using_jtag [2008/08/02 19:48]
newell Adding example of slotted back for JTAG connector
+++ 20b:using_jtag [2008/08/02 21:20] (current)
newell Fixing typos, adding Mouser part number for suitable JTAG connector.
@@ Line 1: / Line 1: @@
+To use a JTAG interface, you will need 3 items:
+- a modified calculator
+- a JTAG interface
+- a program that can use the JTAG interface.
+The calculator needs to be opened, and a JTAG header needs to be soldered. The JTAG header is a standard 16 pin Berg SMT header with 2.54mm spacing. I have a picture, but I do not know how to upload it, so if someone that know how that whole wiki knows, please drop me an email and I will send you the picture.
+The soldering job is easy, even for a SW engineer. You can use a simple $20 soldering iron from Radio shack if you do not have one (I use a gas powered one personally)..
+I advise that you make a hole at the bottom of the calculator in order to allow to close the calculator back up while still having access to the JTAG (here again, I have a picture)... the hole should cover the height of the recessed space at the bottom of the calculator back and be around 4.5cm wide.
+Then, install the JTAG drivers, connect the JTAG interface to the PC and the board and you are ready to rock and roll.
+I use the Atmel SAM-ICE JTAG (around $150 or so) available at Digikey or Mouser....
+For the PC side, I use the IAR tools, and I advise that you use them also as the demo projects given by HP are using them also.
+Compile the project, 'debug' and here you are!
+They are however restrictions.
+- The debugger has only 2 breakpoints that you can use (because the ARM has only 2 hardware assisted breakpoints).
+- Programming works much easier if you erase the flash first manually.
+- The debugger does not work if and when the CPU goes in sleep or OFF mode. (This is why I always debug with the calculator in 'TestSystem' mode.)
+(Here's what my JTAG slot looks like.  It's about 1.1" by 0.35".  Now that I've put it all back together, the JTAG IDC connector is just a little close, so I should have extended the slot down closer to the bottom rubber foot.  I tried to avoid digging too deep into the area where the back door latches engage.  The plastic is soft; I used a Dremel with a carbide burr and had no trouble at all.  --newell)
+{{20b:jtag_slot.jpg}}
+(For the 16 pin JTAG connector, I used an FCI 95278-101A16LF from Mouser, part number 649-95278-101A16LF, $0.75/each.  Before the connector
+arrived, I was using 24" lengths of wirewrap wire soldered to the JTAG pads, and that worked fine, but it was a bit messy.  --newell)

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