Honored Contributor
Honored ContributorHi,
I took a look in the handbook and maybe you could check something additional... Acc. handbook the "Reset completed" is indicated by nConfig and nStatus both being high (ch. 8). This could validate the Cyclone is ready for configuration to check the 1.0/1.2 V issue (in fact, I would think the 1.2V on the Cyclone IV shall not cause direct failure (otherwise you would observe high current consumption / overload on the internal 1.2V regulator or a hot Cyclone). Nevertheless (assuming it's not a selection process like the speedgrades were on some intel Processors) this overvoltage will not extend the operational life... Regarding the USB-Blaster I/F (Pin4, VCCA) the Blaster must be powered by 2.5V as the internal circuits are not compatible with lower operation voltages. ("You must power up the VCC of the download cable with a 2.5-V supply from VCCA. For device using VCCIO of 1.2, 1.5, and 1.8V refer to Figure 8-24"). Thus first is to disconnect Pin4 from the board and apply 2.5V to power the USB Blaster... IMHO Besides this - the VCCA is always 2.5V (being the supply for the PLL) and must be applied even for circuits not using the PLL - maybe you also need to check the routing for the VCCA pins... I'll cross fingers :-)
