Malcolm Hartnell

USB reset

Discussion created by Malcolm Hartnell on Apr 6, 2006
Latest reply on Apr 6, 2006 by Malcolm Hartnell
I'm working through the steps on page 28-48 of the MCF547x Reference Manual (Rev 3) in order to initialise the USB module on a 5474. It is my understanding that the USB reset in step 1 (set USBCR[USBRST]) results in the RSTSTOP interrupt in step 7 but I am not seeing this interrupt. I have the relevant interrupt unmasked and the appropriate interrupt level and priority enabled but I don't see the interrupt status register change which should change even if the interrupt is masked.
As a quick test I tried to poke a long to USBCR of value 4 (USB reset) and expected to see bit 5 set in USBISR to indicate the end of the reset but this does not happen. Can anybody tell me what I may be doing wrong or is the RSTSTOP interrupt not triggered by a USB reset initiated by USBCR[USBRST] ?