The chip definitely requires that the DREQ signal be used to start a DMA transfer. That is even if you are doing memory-to-memory transfers.
See section 16.6.3.7 in the Reference manual. Bob fishcamp engineering 105 W. Clark Ave Orcutt, CA 93455 TEL: 805-937-6365 FAX: 805-937-6252 -----Original Message----- From: [EMAIL PROTECTED] [mailto:owner-linuxppc-embedded at lists.linuxppc.org] On Behalf Of Hihn Jason Sent: Friday, July 12, 2002 10:06 AM To: linuxppc-embedded at lists.linuxppc.org Subject: Software triggered DMA on 823e? We're doing a design and due to the way some of our devices work, we want to do a DMA transfer on an interrupt from a peripheral. My team is wondering if we can write a interrupt handler that will initiate the DMA xfer without having to use external pins, or if we have to route an output pin to DREQ and trigger it that way. Our peripheral is a memory mapped device, but it's only a buffer. We need to catch its interrupt and DMA the buffer out to a place for our application to handle it. We've been all over the manual and can't find the answer. Any help is appreciated. ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
