405GP and external masters
From: Brian Kuschak <hidden>
Date: 2001-07-09 21:26:31
I hope someone here has experience with the 405GP and external masters. Regarding burst-capable External Bus Masters on the EBC on the 405GP ... "Once an external master owns the peripheral interface it can read and write all PLB- and OPB- addressable memory, with the exception of devices controlled by the EBC." If an external master initiates a burst write to an address in SDRAM, does the the data go directly to SDRAM, or does it go to the cache instead? I would guess SDRAM since the 405 doesn't snoop. Are there any other restrictions on this type of transfer, other than the address being aligned on a cache-line/burst boundary? During the burst, is the PLB tied up for longer than usual, since the burst is coming from a 50MHz bus onto a 200MHz (PLB) bus, or does the EBC buffer this burst like the DMA controller does? Thanks in advance. Brian ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/