Subject: Re: NEW_SCC_DRIVER problem
To: Izumi Tsutsui <tsutsui@ceres.dti.ne.jp>
From: Jason R Thorpe <thorpej@zembu.com>
List: port-alpha
Date: 11/05/2000 08:01:17
On Sun, Nov 05, 2000 at 09:56:31PM +0900, Izumi Tsutsui wrote:
> I took a look at zstty port on my 3000/300 with TCWSCONS kernel.
> It can send/receive charactors but does not handle RTS/CTS nor
> DCD/DTR at all. Then I notice comments in tc/scc.c:
>
> * NOTE: The wiring we assume is the one on the 3min:
> *
> * out A-TxD --> TxD keybd or mouse
> * in A-RxD --> RxD keybd or mouse
> * out A-DTR~ --> DTR comm
> * out A-RTS~ --> RTS comm
> * in A-CTS~ --> SI comm
> * in A-DCD~ --> RI comm
> * in A-SYNCH~--> DSR comm
> * out B-TxD --> TxD comm
> * in B-RxD --> RxD comm
> * in B-RxC --> TRxCB comm
> * in B-TxC --> RTxCB comm
> * out B-RTS~ --> SS comm
> * in B-CTS~ --> CTS comm
> * in B-DCD~ --> CD comm
>
> This means channel A and B is _not_ independent.
It's true of all TC Alphas and the TC DECstations that have the SCC
chip, as well. In fact, it's because we currently don't handle the
cross-wiring of the devices that the NEW_SCC_DRIVER is not the default.
Bill Studenmund and I had some ideas on how to fix the problem, but we
changed jobs before we had a chance to implement them. I need to get
my 3000/300 set up so we can work on it again.
--
-- Jason R. Thorpe <thorpej@zembu.com>