On Thu, Jun 03, 1999 at 05:21:43PM +0100, Jason Flynn wrote:
> 1) What IC would be a good move 85C230 or 16C3x or
> something different again ?
I would NOT make an ISA design. There are already too many
of them (although I yet have to find a really good one).
If I had the time, I'd go for PCI and a 16C30 USC.
And don't forget, I want to see both channels operating
simultaneously at 10Mb/s full-duplex ;)
> 2) What is a good way of getting the data of the SCC IC?
> ISA DMA? DMA into on card memory mapped RAM ?
IIRC, I saw some commercial USC cards having just external FIFO
chips and a PCI busmaster interface.
> 3) What are the issues with running both channels
> of a Dual channel IC in DMA mode?
> 4) What are the issues with running full duplex
> and DMA ?
If you are running full-duplex, you would require 4 DMA
channels on ISA. For higher data rates the SCC/USC's on-board FIFO
is WAY to small. And be VERY careful about SCC DMA write cycles
and the ISA specification. Neither PI2 nor PackeTwin do it
right.
> PPS can anyone point me to an online manual for
> the 85C230?
SCC, USC, IUSC - data sheets, user manuals - It's all on www.zilog.com.
-Klaus
