Honored Contributor
Honored ContributorSome oscilloscope screenshots that may help:
Screenshots taken at board power up, triggered on the first falling edge of nCS of the EPCQ devices (CH1 - top trace) Left-hand side: board with EPCQ32 (working well) Right-hand side: board with EPCQ32A (Configuration fails) Auto-restart configuration after error: enabled DCLK starts at 12.5 MHz. After some time DCLK goes to 100MHz, according to the "Active serial clock source: 100 MHz internal oscillator" setting. On the board with the EPCQ32 device, the configuration lasts for tens of milliseconds and is successful. On the board with the EPCQ32A, we counted approximately 1664 clock cycles @ 100 MHz; after that nCS goes hi and the configuration process is aborted. Setting the "Active serial clock source" to "12.5 MHz internal oscillator" does not change the behaviour: after the same number of clock cycles (approx. 1664) from where the clock frequency was supposed to change (in fact, with this setting it does not change), nCS goes hi and the configuration process is aborted in the same manner CH2: DCLK https://www.alteraforum.com/forum/attachment.php?attachmentid=15290 CH2: D0 https://www.alteraforum.com/forum/attachment.php?attachmentid=15292 CH2: D1 https://www.alteraforum.com/forum/attachment.php?attachmentid=15293 CH2: D2 https://www.alteraforum.com/forum/attachment.php?attachmentid=15294 CH2: D3 https://www.alteraforum.com/forum/attachment.php?attachmentid=15295
