[P] MECB Z80 CPU Card

[epaell]

Thanks David,

I do have some alternate serial devices on order which I'll try once they arrive. It just seems strange that it doesn't work without hardware hand-shaking i.e. I can load software via the monitor with no problems. Of course, there might be extra overheads involved with XMODEM (I'm not really familiar with the protocol) but I would've still thought there should be enough grunt to handle it at low BAUD rates). There also seems to be a rush of characters sent to the terminal after the transfer times-out which I also find unusual - almost like it is not even checking the status of the serial port. I'll see if I can find a version of kermit somewhere and try that. It's not anything critical - just something that I found a bit annoying as it seems like it should be something that just works. I notice that there is also a DOWNLOAD.COM but that seems a bit clunky as you need to convert your file into another format before transferring - I guess I should try that as well but it's not my ideal choice. Anyway, I have a few things to try - I was more curious as to whether I was just doing something completely wrong.

[djrm]

Probably not much help but XM is working for me.

Code: Select all

B>xm r a:junk.txt
XMODEM v12.5 - 07/13/86
RomWBW, 30-May-2020 [WBW], HBIOS FastPath on COM0
Receiving: A0:JUNK.TXT
230k available for uploads
File open - ready to receive
To cancel: Ctrl-X, pause, Ctrl-X
CK
Thanks for the upload
B>

I'm using a FTDI USB to 5v adapter with CoolTerm on a M4 Mac. I selected CTS handshaking in coolterm. baudrate is 38400 bps.
I think Ive had problems in the past where transfering to ram disk was more reliable than using IDE devices.
hth David.

edit: just checked, its an FTDI serial adapter

[epaell]

Thanks for running that test. Just to check was this running on the MECB Z80 with the 6850 serial connection or on the RC2014? I just tried via a Raspberry Pi and had the same issue. I'll try and get CoolTerm just to ensure it isn't some weirdness with minicom.

[epaell]

Ha, looks like it is something weird with minicom - I just tried it with CoolTerm and it worked fine even without any flow-control.

Thanks for helping me debug this - at least I know it is not something weird with the MECB hardware or software now

[djrm]

Yes XM was tested with MECB 6850. It didn't work for me without cts flow control at 38400 bps. Glad it's working for you now, David

[epaell]

Hi David,

Perhaps the faster 10 MHz Z80 I have on mine helped to push it over the line for 38400 usage?

By the way, I connected up to the Fujinet discord group. It looks like there is still quite a bit of discussion with respect to how to implement the interface to the ESP32 device (which does all the grunt work) on the RC2014. i.e. whether it be a parallel connection via an 82C55 (as in the H8/H89) ... which in itself seems to be taking a long time to develop (over four years, I would've naively thought this to be a relatively simple alternative), using the SPI interface (for which they are debating various implementations), or going via a UART. I can definitely expect a great deal of effort required on the software side (on both sides of the interface) but I'd have to admit that I'm a bit surprised that the interface itself seems to have been a sticking point for so long (over four years for the RC2014 as well).

Emil.

[djrm]

I had a look on the Fujinet discord, the RC2014 version seems to be very much in flux with parallel, serial, and spi contenders.
I have an Apple II here for repair, I'm tempted to try and get it working with Fujinet - need to fix it first though.

I have not yet managed to get a CF interface woorking, Your boards arrived yesterday and will try one shortly, but need to wait for some connectors to arrive first.

A post I made yesterday has vanished, the jist of it was:
T-Net gives you access to files on your PC via a serial port.
T-Net is easy to implement just needing a spare serial port (do you have one?)
The CP/M drivers already exist and work.
The source code and lots more too is available on John Hanson's website:
https://www.cccplusplus.co.uk/xbeaver/x ... vault.html
source files exist for various UARTs, I highly recommend and shall dig it out when I get the CF interface working.

Best regards, David.