plasmo wrote:
maded2 wrote:
plasmo wrote:
Mine USB blaster is just a cheap $5 clone.
Maybe 7128S is different than 7064S regarding the JTAG enabling. Or perhaps the 7128S you have are something else. I'm interested to try the JTAG enabling method on 7128S. Did you buy yours from eBay?
Maybe 7128S is different than 7064S regarding the JTAG enabling. Or perhaps the 7128S you have are something else. I'm interested to try the JTAG enabling method on 7128S. Did you buy yours from eBay?
thanks,
eddie
I received 4 pcs EPM7128SLC84. I verify their JTAG ports are locked. Three of the 4 parts draw fairly high current, 200-300mA; one draws about 100mA. I have a proven programming fixture for EPM7128SLC84. Only signals hooked up in the programming fixture are power/ground and 4 JTAG signals. I added a 1K resistor to OE1 (pin84) where 12.5V can be applied through the 1K resistor. I apply 5V first and 12.5V next. I was able to erase the JTAG lock for the part with low current. Once JTAG is re-enabled, it programmed normally. However, with the three high-current parts, I was not successful in erasing the JTAG lock. I've tried many times, but failed every time.
Here is what I've observed with the successful part: I programmed with a working EPM7128SLC84 POF file. The programmer reported unsuccessful JTAG connection and programming appeared to have failed, but once I removed 12V and recycled 5V, I'm able to establish JTAG connection and program the part normally.
So there is a small success, but more works are needed to reliably erase the JTAG lock.
Bill
It's a step forward at least. I think those chips with high current draw maybe dud onces as I've no way to test it. Is the 12.5V the minimum?
anyway many thanks for your work.
eddie