Need help updating synth with AVR programmer

[LoGiCa]

Hey, not sure if I have posted this in the right section.

I am trying to work out how to update this DSP synth I have which is no longer supported by the manufacturer http://www.use-audio.com/plugiator.htm

I managed to get the firmware update package from one of the companies distributors and have been looking over the update procedure which seems quite straight forward.

The problem is that I dont know what type of AVR programmer to get to perform this update (ATMEL AVR Studio 4.12 was installed so I guess any compatible AVR programmer will do?) . Also I can't find where I could source the “Target power adaptor” as described in the pdf below.

I dont think the “Program Enable” adaptor mentioned at the end of the document is needed as there is a jumper shown below on the opposite side of the PCB. I assume its just a case of moving the jumper to the other pins?



The update procedure PDF

Any help with this would really be appreciated.

[LoGiCa]

I guess the Target power adaptor provides more voltage to the IC but is there a programmer that has this built in?

[Stephanie]

The target power adaptor doesn't provide more voltage, it provides more current. From the looks of it, they are using two USB cables to provide twice the current. USB ports can provide up to 500mA but if the synth draws more than that, it will cause the programmer to fail, or the computer may shut off the usb port if it senses the current draw to be too great.

As for what type of programmer, the Adafruit one http://www.adafruit.com/index.php?main_ ... 8aa4b5c09f would be fine I am sure -- other than the question of current.

You are probably correct about the program enable adaptor, it appears to be just a matter of shorting the jumper in order to enable reprogramming the chip.

You could enquire with support about the programmer and the current considerations. An other way to handle it *might* be to let the synth provide its own power, i.e. plug the synth in and turn it on, so that it isn't drawing its current from the programmer. You'd have to research this possibility further however as it may not be practical, or it might cause other problems. I know with some programmers, there is the option (usually a switch or something) that sets whether or not the Vcc from the programmer is connected to the circuit -- in other words, leave the circuit under its own power and don't try and power it with the programmer.

Cheers

[LoGiCa]

Thanks for the reply.

It all seems strightforward except for that USB power adapter. The synth is powered from a 9v 500ma adapter so it might work if I flashed the unit while plugged in.

I think the idea of these adapters was to make the distributors job easier when the units where RMA'd for the update as its a painfully buggy unit without the update.

[Stephanie]

You just want to ensure that the 9v on the synth does not get into the AVR programmer.

It looks like the Adafruit programmer does have a jumper that isolates the Vcc which is what you want. J3, "USB power to target". You'd want to remove that jumper, then the synth can be powered with it's own supply while the USBtinyISP provides the programming data. This should eliminate the need for that target power adaptor.

Cheers!

[LoGiCa]

Awesome!, thanks for sharing the knowledge. I appreciate it.

[LoGiCa]

Do you think this mod to the AVRISP MkII would also work?

AVRISP MkII Mod

[Stephanie]

It should work. Just don't do the mod you linked to, as you don't want to be providing power to the target board in this case.

Cheers!

[LoGiCa]

Hi, thanks for the reply. Could you explain why the modded AVRISP would be different and why I should not do it this way.

I'm still learning so it would be good to understand the difference.

Thanks!

[Stephanie]

The mod that is described there is specifically to allow the programmer to power the target board. In the case of your synth, you're going to be powering it through its 9v 500mA supply so you do not want the programmer to also be supplying power - that would risk the 9v on the board burning out the 5v programmer.

With the USBtinyISP there is a jumper that lets you select if you want to power the target board or not power the target board, which is why it is a good choice - in many cases, it's easier and preferable if the programmer can power the circuit while you are programming it.

With your synth however, it appears to require more power than a USB programmer can provide (hence the 'target power adaptor' that was described in the programming pdf). So instead of relying on the USB programmer to power the board, you can probably just power the board with its own power supply, but this means that your USB programmer must not try and power the board (target) at the same time.

[winch]

The programmer in the pdf probably is an AVRISP which thanks to the link to the mod we know does *not* supply power to the board being programmed.
That's why they use the target power adapter to splice in 5v from a usb port.

A modified AVR ISP or another programmer like the usbtinyisp that supplies 5v to the board should work fine.

[LoGiCa]

The programmer in the pdf probably is an AVRISP which thanks to the link to the mod we know does *not* supply power to the board being programmed.
That's why they use the target power adapter to splice in 5v from a usb port.

A modified AVR ISP or another programmer like the usbtinyisp that supplies 5v to the board should work fine.

I was hoping that was the case. I will give the mod a go and report back. Thanks for the info guys.

[LoGiCa]

Does anyone have any recommendations for a pre-built AVR programmer (not a kit like the USBtinyISP) that can supply 5v power to the target board?

[Stephanie]

Does anyone have any recommendations for a pre-built AVR programmer (not a kit like the USBtinyISP) that can supply 5v power to the target board?

I like the Sparkfun AVR Pocket programmer. It's cheap, comes with everything you need, and it is based on & fully compatible with the USBtinyISP. It's not a kit, comes fully assembled, and has a switch so you can power the target or not.
http://www.sparkfun.com/products/9825

[LoGiCa]

I got a reply back from the manufacturer of the synth, but not answering any of the questions I was asking. But they did send the picture below which helps alot.

Also there are 2 updates involved I am told. 1 which updates the top panel interface which is pictured below and the other which you plug the programmer into the main board of the synth and power the traget board with the units own 9v power adapter.

I just need to find a programmer with +3.3v now...

I was also right about the program enable adapter, it does just bridge the pins the same way the jumper does on the other side of the board.

Does anyone have any recommendations for a pre-built AVR programmer (not a kit like the USBtinyISP) that can supply 5v power to the target board?

I like the Sparkfun AVR Pocket programmer. It's cheap, comes with everything you need, and it is based on & fully compatible with the USBtinyISP. It's not a kit, comes fully assembled, and has a switch so you can power the target or not.
http://www.sparkfun.com/products/9825

Thanks for the info. Does this programmer supply +3.3v?