New tech must have burned these production mega16 boards with the wrong fuse settings… The jtag wont detect… we designed the bds with a jtag connector but no isp connector… someone suggested I might be able to hook up the ISP lines with those SMD micrograbbers to the STK500 ISP and try to erase the chip (12V on the reset or something?). So have I described my problem? We messed up and progged a dozen of these bds with the jtag off… Any way to erase/reset the fuses and start over? Does the kludge with the micro grabbers sound like it will work? Hey Sparky: you guys gonna carry the Pomona SMD grabbers?
Those are cool!
http://www.pomonaelectronics.com/html/m … rabber.htm
No - we don’t carry them. A little too exotic for us.
I am not handy enough with the AVR parts to really say - but I believe you have to have the JTAG fuse set to use a JTAG. If your tech has gone and erased them, you’ll probably have to use a hardware prog (AVR-PG1) to set the JTAG fuse again.
-Nathan
Hi! Thanx for the reply… hopefully someone can chime in here… the main prob is these are the 44 pin flatpacks soldered on the bd. My idea is to get the smd grabbers on clk miso, mosi, vcc and gnd and plug the other end into the stk500 isp header and try to hi voltage erase em. AT that point, jtag will proably wake up again (I hope). This sound ok?
I see no reason that an SPI programmer would not work assuming the tech did not set the SPIEN fuse to 1 (which disables SPI programming). Also, you don’t need 12V on reset for SPI programming-- SPI is entered when RESET is pulled low and an ident sequence sent on MOSI/SCK.
The challenge you have is related to what SCK, MOSI and MISO are connected to on your design. If any of these pins are being used as inputs then you will likely be unable to program it. Good luck.
We have a jtag connector on the bd, so the jtag pins just go to that connector… I never had a problem, but I wasnt watching this guy push buttons, all I know is the bds he programmed dont detect the jtag anymode… so I was thinking one of the clk fuses got messed up… but I cant read the fuses or id with an isp rig up to the stk500 using little smd grabbers, or the jtag. Wonder how you can clobber the jtag like that?