CPS8256 serial port reliability

[JonB]

Hi


Anyone have experience using the CPS8256 serial / parallel port on the PCW? I ask because I am encountering lots of transfer failures via Kermit at 2400 baud (!) . I am using 2400-8-N-1 setup with no hardware handshaking. I've done this previously (on a big Tandy machine) and got reliable transfers at 9600 baud.


Cheers
JonB

[jevicac]

Hi, See our link (Spanish)

http://www.pcwwiki.amstrad.es/doku.php?id=es:hardware:comunicaciones

Test with1200,N,8,1

[GeoffB17]

Jon,


Long, long ago, I did a certain amount of transferring using the CPS module.


This was linking the PCW to an Epson HX-20, and also to a BBC.


Can't remember what parameters I was using, I'm sure something faster than 2400.   I don't remember ever having any problems.


I used progs in BASIC, C and also the MAIL232 prog supplied.   Never did much linking to the PC (if any ?) as it was easier to use disks.


I'll try to find some of the progs I was using.   I'll have the code somewhere, 'filed' on a disk?


Geoff

[GeoffB17]

Jon,


Still having the problems?


I've now found some (?) of my bits about the link I was doing.


As far as I can tell, the prog I was using to link the PCW to the HX-20 was for transferring FROM the HX-20 to the PCW.   I don't think I was running anything the other way.


The prog I'd done is actually Z80 ASM.   The prog is using software handshaking, i.e. ACK/NAK with a CHK, with any hardware hs turned off.   Looks like I was using SETSIO at the PCW end to prime the PCW SIO.   I seem to have 3 versions of the prog, the last version had an option to define the receive drive (A:, B: or M:), so I think the changes were not THAT great?   I cannot remember what speed I was using, may in fact have been no more than 2400, but I was using a fairly long cable, prob null modem.


If any of the prog I did is useful, let me know.   I've still got the .ASM files as well as some .COM


Geoff

[JonB]

Hi Geoff


I'd love to see your program (asm and com) if you're willing to share.


Meanwhile I think I may have worked out what the problem is, after looking at some Amazon reviews of various serial port adapters. One of them said the adapter in question needed a powered USB hub because his PC didn't put out enough juice to run the adapter. That struck a chord as I use a small laptop with a hub connected to a keyboard and wireless mouse. So I plugged a 1A power supply into the hub and so far I am getting a reliable 9600 baud transfer with no handshake.


Wish I'd sussed this out sooner. I've been  building an image for uIDE at 2400 baud and so far it's taken days..