Post Go back to editing

unable to reset rd_rdy in BF549 NFC

I'm looking at a BF549 via JTAG and trying to read out data manually from a NAND flash attached to the NFC but I never can get more than one byte out.

- reset board/processor

- disable interrupts

- configure portj fer & mux

- configure  NFC_CTL

- W1C all NFC_IRQSTAT irq's to clear; NFC_IRQSTAT now 0x0

- try to do a READ_ID from the device with

  NFC_CMD = 0x90

  NFC_ADDR = 0x20


  read NFC_READ => 0x4F  ; this correct, first byte of ONFI

  NFC_IRQSTAT = 0x08 as expected (RD_RDY); but I cannot clear it with W1C's to this register

this kind of indicates the NFC doesn't believe I ever read the data, but clearly I did and got the right info.  trying to process more bytes does not generate any additional read cycles to the NAND as you would expect with the stuck IRQ.

what am I missing?  I have tried all kinds of memory access sizes for the registers and delays as well as two completely different technologies of jtag equipment & software.

I can't see how this could be related to anomaly 05000500.