On Sat, Apr 01, 2000 at 12:58:47AM +0200, Andreas Johansson wrote:
> Would you care to explain just how the PCI Cypress device would only
> affect the ISA bus?
>
Because cy82c693u is a single chip with integrated IDE/ISA/USB/RTC/Other
PC junk. USB is not used on sx164, so the chip actually is the PCI/(IDE+ISA)
bridge with its own (yes crappy) arbitration between ISA and IDE DMA.
You can find more info in the cy82c693u datasheet available at
ftp://www.cypress.com/pub/datasheets/cy82c693u.pdf
> Your example may very well hold true, but it does not prove your
> theory.
I'd rather call it practice :-)
> How much FIFO do you have in respective sound card, how
> large transfers are done through the PCI->ISA bridge, etc. ?
>
I don't have docs but I doubt that PCI audio chips have large FIFOs.
> Ok, you're right, the card doesn't do a full 64kB transfer, it only
> transfers 0x50 32-bit words (I guess) per transfer. How many PCI cycles
> this means, I don't know. Probably more.
>
Hmm, from cy82c693u datasheet:
As a PCI master, the CY82C693U will
only perform memory read and write transactions. A write cy-
cle consists of a maximum of 4 bytes of data in a single data
cycle. A read consists of a maximum of 8 bytes in a two cycle
burst.
Ivan.
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