Hello,
I mistakenly used an EPCS16 (8-pin SOIC) in my design with a Cyclone III EP3C120. Active serial has been working but if I use more than half the chip then my program will probably not fit in 16Mb anymore. I ordered an EPCQ32 (same 8-pin SOIC package) and put it on the board and I can program the EPCQ32 but the FPGA does not load. I tried programming directly via the USB Blaster and active serial header as well as through the FPGA using JTAG. The chip programmed successfully both ways but when I examine the EPCQ32 I sometimes get a bad CRC. I tried removing the USB Blaster and cycling power with no luck. I probed the pins with a scope and it appears to be trying to load so I left it for a couple hours and when I came back it had loaded. I tried removing the active serial protection diodes and caps but that did not work either. Should an EPCQ32 work with an EP3C120 or am I doing something fundamentally wrong?
I mistakenly used an EPCS16 (8-pin SOIC) in my design with a Cyclone III EP3C120. Active serial has been working but if I use more than half the chip then my program will probably not fit in 16Mb anymore. I ordered an EPCQ32 (same 8-pin SOIC package) and put it on the board and I can program the EPCQ32 but the FPGA does not load. I tried programming directly via the USB Blaster and active serial header as well as through the FPGA using JTAG. The chip programmed successfully both ways but when I examine the EPCQ32 I sometimes get a bad CRC. I tried removing the USB Blaster and cycling power with no luck. I probed the pins with a scope and it appears to be trying to load so I left it for a couple hours and when I came back it had loaded. I tried removing the active serial protection diodes and caps but that did not work either. Should an EPCQ32 work with an EP3C120 or am I doing something fundamentally wrong?