Re: New driver for Opcode 64X Serial MIDI interfaces

["Bill Adair" <adair@gotadsl.co.uk>]

On Fri, 25 Feb 2005 14:12:17 +0100 (MET), Clemens Ladisch  
<clemens@ladisch.de> wrote:

> Bill Adair wrote:
>> Do you want me to (a) provide a replacement file for
>> serial-u16550.c, (b)  provide a version of serial-u16550.c with
>> comment documentation in but no Opcode driver and a seperate
>> Opcode driver file, or (c) provide just a comment documented
>> Opcode driver and leave serial-u16650.c alone?
>
> If the Opcode is similar enough to other serial devices (BTW: what are
> the differences?), there's no reason to put it into a separate file.
>
> Please submit one patch for each logically independent change.
>
>
> Regards,
> Clemens
>

The Opcode device is similar to the others in that it uses F5 for channel  
changing.
The major differences are it's relative modernity and therefore throughput  
speed
(the device runs at 115200 baud), the sign on sequence demanded by the
interface before allowing any midi traffic, a sign off sequence required  
at the end
of use, and the signalling required to prevent midi traffic choking. Every  
four bytes
sent to the interface the computer must wait for a _toggle_ of CTS (there  
is nothing like
this in the current drivers) and every 16 bytes sent to the pc the  
interface waits for a
_toggle_ of RTS. The device can also be indentified as being on the serial  
port which the
driver does (instaed of just checking for a UART chip).

Bill



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