Hello All,

In order to flash the firmware and do low level programming on a fez (specifically cerb40) one would need to use a jtag programmer correct? If so then has anyone ever turned a Fez (of any kind) into a jtag programmer?

The JTAG protocol is not all that complex. It’s based on SPI. The problem will be to make your JTAG programmer compatible with your programming/debugging software.

It might be easier/faster to either look at an open source FTDI based JTAG programmer, or to buy one of the $10 STM32F4DISCOVERY kits that come with a JTAG programmer that can be connected to custom boards too…

@ andre: Ultimately, I am building a single board stepper motor controller based on the DSPIN L6470 with integrated Cortex-M3 processor (based on Cerb40) that includes motor temp sensors (one wire temp sensor ic) and K-Type thermocouple temp sensors. Also the board will have one 60A mosfet for controlling large loads (i.e. heating elements). It will also have PWM fan control (for speed controlled fans), and an input for a potentiometer so that the entire thing is closed loop.

But for now I just need to be able to flash the Cerb40 so that I can load the .NETMF framework onto blank chips when it’s time to go to production.

If you don’t need debugging ability then why not just use the USB port on the Cerb40 and the DFU tool?

@ Errol, (almost called you error again ;P) Because I would like to have debugging capability. I’ve learnt that being able to attach a debugger helps speed the development process along significantly.

Then the simplest is really to use an STM32F4 dev kit.

You can get an FT2232H based board to be seen by OpenOCD as a jtag board, but it took me about a day to gte set up, and the board was more expensive than the STM32F dev kit.

Ahh, I see that the F4 dev board is inface $15.

But you can also get the F0 board that costs $8. It has the same STLINK debugger onboard, as far as I know…

Both boards have two jumpers that you remove then you can use the onboard debugger for custom boards via a 6 pin header.

BTW, note that the dev boards doesn’t have JTAG, they have SWD, which is a low pin count equivalent for JTAG.

@ Errol, I also need a way of programming the chips in circuit.

Yes, remove the two jumpers on the dev board. Then connect the programming header from the dev board to the programming header on your PCB and program or debug to your heart’s content.

Oh I get it, the eval card can also program another chip if you move the jumpers. Sorry that took so long to compute