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Altera_Forum
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10 years ago

problem programming old cpld (epm7032)

HI, I have thi problem: - old design and HW based on epm7032 (5V) - epm7032 pof file generted with maxplus vers. 9 (I hve the sources) - the design use the JTAG pin (TMS, TCK, TDI, TDO..) as...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
10 years ago

Dear,

I have a similar problem, trying to program old EPM7192S and EPM7128S. What I have noted is that the TDO signal coming from the EPLD device, does not get enough voltage level to hit the logical level "1". The TDO signal voltage level hits at maximum 2V, during the programming operation. Its looks like the TDO signal driver does not have enough capability to drive the input on the USB Blaster or the USB blaster input to TDO signal has a low impedance.

With that same USB Blaster I can program devices as EPM3064A, devices one generation after 7000S family. Although I also have noted that the TDO signal level does not hit so high level as it should be. But it gets 3V, that is enough for a comprehensive logic level "1".

Does some one has a suggestion to solve this issue or even has noted a similar behavior?