Using OpenOCD with the Actel SmartFusion Eval Board

•April 9, 2011 • 3 Comments

I just got this new SmartFusion Evaluation board from Actel. On it is a cool chip that a combination FPGA, analog processor, and Cortex-M3 microcontroller. The board has a built-in JTAG programmer that uses the Actel toolchain to download new designs into the chip, which is pretty nice. However, you can’t debug the software on the microcontroller with it.

So I decided to see if I could get OpenOCD working with my Olimex JTAG-Tiny USB JTAG tool, since there was a 20-pin ARM JTAG header on the board as well. On the first go, it didn’t work, so I decided to look at the signals on my ‘scope. Turns out that the TRST and TCK lines were wiggling, but only at about 1V when they should have been at around 3.3V. I downloaded the schematics from the Actel site, and this is what I found:

SmartFusion Eval Board JTAG Circuit

SmartFusion Eval Board JTAG Circuit

Turns out that those lines had very strong pull-downs on them. Coupled with the 330 ohm, series output resistors, these pull-downs created a voltage divider that was pulling the signal down to around the 1-2V level.

So I fired up my soldering iron, and replaced the resistors with some 4.3k ohm resistors that I had near my desk. And after hooking everything back up, I was able to halt the processor and look around in memory.

Hopefully I’ll be able to get the eNVM flashing over JTAG working in OpenOCD soon.

TL;DR: Remove R14 & R15 and replace with >5k ohm resistors.


HVAC Controller Progress

•September 12, 2010 • 3 Comments

I got boards back from BatchPCB and have almost fully populated one. Digikey sent me the wrong resisitors, so I have to see if I can get the right ones. Take a look:

There are a couple of problems with the layout that I need to fix in the next revision, but I should be able to get going. Now on to programming the darn thing!

Progress on the HVAC Controller

•August 24, 2010 • Leave a Comment

Some progress on the HVAC side of things. I got a preliminary circuit made and PCB in the works. I’m hopefully going to use this as an excuse to tinker around with the Arduino stuff. Take a look:

HVAC Circuit Board

Once I get it working, I’ll release the designs and code.

Silencing of the Wii’s

•June 1, 2010 • 1 Comment

So I went out and got the new Super Mario Galaxy 2 game the other day at Fry’s. I hadn’t hooked up my Wii in quite some some and I had to dig out my video capture card and audio cables to hook the Wii up to my computer. When I go to play the game, I’m greeted with an awful cracking caused by the clipping of the Wii’s audio as the System Menu plays its little intro sound. Somehow I had gotten it to play nice with my computer before, but it’s been so long, I’d forgotten. Having some spare time on my hands, I’d figure I’d fix the problem once and for all.

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Restoring old firmware on a Dlink DCM-202

•March 27, 2010 • 4 Comments

If you’re like me and tried to upgrade your Dlink DCM-202 firmware only to find out that afterwards the telnet shell is no longer accessible, then this is the guide for you. I’ll describe how to recover the old version of the firmware so that you can try other firmwares as they become available.
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More Notes

•November 16, 2009 • 2 Comments

Specs for the LEDs used for the backlight in the stock display unit:

Vf = 3.7 V
I @ Vf = 18.3 mA

Truth-table for the Mode feedback signals (1=open):

Vent Vent+Floor Floor Floor+Defrost Defrost
Mode 1 0 1 1 0 0
Mode 2 1 1 0 0 1
Mode 3 1 0 0 1 0
Mode 4 0 0 1 1 1

Accord ’06 Carputer – Schematics and Pinouts

•September 27, 2009 • 1 Comment

For my own information these are the block schematic diagrams of the HVAC system and pinout of the 22-pin connector that controls all the fans and flap motors.

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