Mine also come from China, fuse locked
, (because I cannot read/program them with a USB Blaster, nothing found on JTAG). Maybe one of the pins is a JTAG enable pin...
My limited understanding, with assumptions, is that for the JTAG devices, if you utilise the I/O's shared with the JTAG pins as user I/O, then of course the JTAG has to be disabled using some fuse. These parts cannot therefore be re-programmed using JTAG. If you do not use the JTAG shared I/O as user pins, then the JTAG remains enabled, allowing re-programisation. Perhaps the 12V on the Vpp re-enables the JTAG I/O. This is something which I will investigate in the future.
In IC design, particularly for low pin count chips, where JTAG is used internally for chip scan test, do you dedicate 4 (or 5) pins to JTAG, so making less pins available for user I/O, or do you share pins and add some mechanism (normally a single TEST pin) to enable JTAG and allow chip scan test? Altera have given maximum flexibility here, and we might assume that the fuse to enable/disable JTAG is "new", i.e. it is not on the non-JTAG devices. We can select to use fewer I/O and have JTAG always enabled, or use maximum I/O but lose JTAG programmability once the chip is programmed.
Having ordered cheap parts from China in the past: Flash ROMs and MC68000 DIL and PLCC, I am now aware of the problem of chip recovery and re-marking.
The MC68000 DILs were 8MHz devices, remarked as 16MHz devices. I found out simply by removing the fake marking with IPA, which clearly revealed the original markings.
The MC68000 PLCC did not work at all. Suspiciously they all had the same date-code markings, but the packages all differed slightly with respect to markings on the bottom and dimples. They were obviously remarked, possibly not even MC68000s. I got a full refund from the seller, who I will avoid in future.
Of the 4 Flash ROMs, 2 worked and 2 did not program. All had identical markings and date code, so obviously re-marked, but the markings did not come off with IPA. My programmer essentially rejected the devices saying that the manufacturer ID was not Intel. I wondered whether the 2 devices which did not program were from another manufacturer, but I could not get them to program when I tried to select different chip vendors. I got a refund for the 2 "broken" devices. Whether I can trust the speed rating of the 2 "good" (and remarked) devices is unclear.
Clearly all the above devices were re-claimed and were not NOS.
BTW I have absolutely no issue with chip recovery, but I simply want the sellers to be honest. Some sellers might buy chips from the recovery companies in good faith, and there will be good and bad recovery companies. What really p*****s me off is when the chips are re-marked. What a waste of time. Given the low selling cost of the chips, why bother?
So I will be interested to find out if the EPM7032S devices are genuine parts and if so, are they locked.