SC114 + Serial I/O and Clock + FTDI232 to USB ???

[r4r...@gmail.com]

Hi, 

I have a SC114 + Serial I/O and Clock + FTDI232 to USB cable, but when I setup on a COM port on my PC to TeraTerm and plug the cable into Port A on the SC114, I don't see anything in the TeraTerm window?  I tried 4800, 9600, 19,200 and 115,200 BAUD.  

I do see the Green LED on the SC114 board and also the Blue Rx LED blinking on the Serial I/O and Clock board.  

I tried connecting to the Serial I/O and Clock board (I'm guessing should be Port B), but still nothing.  

How do I get a prompt of some kind with this?  

[Steve Cousins]

First, try SC114 on its own (without the serial module attached). Connect the USB adapter to SC114.  The serial port on SC114 works at 9600 baud, 8 data, 1 stop, no parity, RTS/CTS hardware flow control enabled. Press reset on SC114. The LED on SC114 should flash off twice to indicate it is running. You should get a prompt on your terminal. If the LED is correct but there is no prompt, try disabling the RTS/CTS flow control in TeraTerm.

If that works, attach the serial module with its address set to 0x80. Connect the USB adapter to the serial module. This serial module works at 155200 baud, 8 data, 1 stop, no parity, RTS/CTS hardware flow control enabled - I believe. Press reset. The LED on SC114 should flash off once to indicate the serial module has been detected. You should get a prompt on your terminal. 

If the serial module is detected (at address 0x80) it is used as the default console device. If not, then the serial port on SC114 is used.

Steve

[Brian Welland]

Hi Walt,

I have just hooked up a SC114 and a 33f Serial + Clock which is identical to yours.

I am using PUTTY with the attached set-up but TeraTerm is basically the same..

Works exactly like Steve has described and attach a screen shot of the displayed output.

Trust this helps.

Brian

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[r4r...@gmail.com]

Hi, 

I unplugged the Serial and Clock module, just using the SC114 when I hit RESET, the green LED comes on solid and there is nothing on the TeraTerm screen.  

Flow Control is set to CTS/DTS, or DSR/DTR, OR XON/XOFF, or none.  None of the flow control settings change anything.  

[Steve Cousins]

If the LED on SC114 does not flash as described in the user guide (and as briefly described above) then the firmware is probably not running correctly (or most likely it is not running at all) and you won't get anything sensible (if anything at all) on the terminal.

Looking at the photo it appears the ROM chip is misaligned (it overhangs the end of the socket).

If that is not the case then the usual fault finding approach would seem appropriate:

1/ Check and double check visually that all the components are in the correct places

2/ Check and double check visually all soldering

3/ Check you have a good clean 5 volts on the actual PCB

If that doesn't solve the problem we need to take some measurements etc.

Steve

[r4r...@gmail.com]

Hi, 

Good eye!   ... I didn't build these boards, a friend gave them to me to play with.  I ReSeated the PROM correctly and now I get the prompt!  

When I plugged the [Serial I/O and Clock] board, I cannot get a prompt.  I guess I'll work on getting Port B up 'n running later.  

I guess now I need to go back to the online manual and learn a little more about this computer for a few more baby steps;  

Load and RUN CP/M 

At the CP/M prompt load and RUN BASIC.  

The next step would be how to add the CFStorage1 board or the CF Card Adapter to have CP/M, BASIC and drives to load and save programs onto.  

[r4r...@gmail.com]

Hi, 

Okay, I found BASIC, it runs, it lets me "Send" BASIC programs from my PC via TeraTerm "Send" to the SC114 and they work too.  

Small Computer Monitor - SC114
*?
Small Computer Monitor by Stephen C Cousins (www.scc.me.uk)
Version 1.0.0 configuration S2 for SC114 motherboard

Monitor commands:
A [<address>]  = Assemble        |  D [<address>]   = Disassemble
M [<address>]  = Memory display  |  E [<address>]   = Edit memory
R [<name>]     = Registers/edit  |  F [<name>]      = Flags/edit
B [<address>]  = Breakpoint      |  S [<address>]   = Single step
I <port>       = Input from port |  O <port> <data> = Output to port
G [<address>]  = Go to program
BAUD <device> <rate>             |  CONSOLE <device>
FILL <start> <end> <byte>        |  API <function> [<A>] [<DE>]
DEVICES, DIR, HELP, RESET
BASIC    Grant Searle's adaptation of Microsoft BASIC
WBASIC   Warm start BASIC (retains BASIC program)
CPM      Load CP/M from Compact Flash (requires prepared CF card)
*

Next I plugged-in the "Compact Flash Storage" v1.0 board with its CF card:

I typed   *CPM, but nothing happens.  I'm guessing since I cannot even find a format on the CF card with my Windows 10 Explorer ... the card is blank or cannot be read by the Windows Explorer.  

I'm guessing I need a set of files and format for the card.  FAT? FAT16? FAT32?  

Are there any suggested .zip files of a good image for the CF card?  My primary starting image would be CP/M 2.2 and MBASIC 5.21 ... but would also like to explore other newer versions of CP/M and BASIC ... especially if GWBASIC could be used.  

[Steve Cousins]

There is a special format for CP/M so Windows Explorer will not read it.

The card in the illustration has CP/M configured for the SIO serial module. You need to install a version of CP/M configured for the serial port on SC114. You need configuration CPM-A from the link below.
https://smallcomputercentral.com/installing-cp-m-2-2-with-scm/

Steve

[r4r...@gmail.com]

Hi, 

Yeah, I found that page and when I try to download the .zip file I have to go into some 3rd party ZipExtractor that I first have to "register" to access and give them permissions.  That's just nuts!  

Does that ZipExtractor write the files directly to the CF card, or does it just collect more info from me before downloading a zip file?  

[Steve Cousins]

I don't understand that. The ZIP files can be extracted with Windows 10's File Explorer.

To be sure I just downloaded "CPM-A_SCM_Apps-2022-03-23.zip" to my downloads folder. Double clicked on it and it opens just like other ZIP files. See attached image.

The ZIP includes utilities (SCM Apps) to format CF cards, install CP/M, and install some common CP/M software.

Steve

[r4r...@gmail.com]

Hi, 

It wouldn't do that for me from Google Chrome ... instead it saved the files on a "Cloud Server" at Google, but I was able to download the extracted files to my PC.  

Following the instructions on the web page:  https://smallcomputercentral.com/installing-cp-m-2-2-with-scm/  This is what I get;  

Small Computer Monitor - SC114

*Ready

*
*g 8000
Compact Flash card format v1.1 by Stephen C Cousins

Card at address $10: Compact flash card not present

Card at address $90: Compact flash card not present
*

I don't see how I can ReConfigure the "Compact Flash Storage v1.0" unless it's something in the rear 6 PIN header or the front 0x10 PIN header.  

I'm starting to think I need a jumper wire somewhere on the board for addressing?  

[Steve Cousins]

You don't need to do anything to the CF module to set the address. As standard, the address is configured as 0x10 to 0x17.

What happens when you type the command "CPM"? You said earlier "nothing". The LED on the CF module should flash on for about half a second.

Here's something else to try. This test reads the I/O port range used by the CF card. If the card is not being read or is faulty the read operations typically return 78. This is just the floating levels on the bus. When the card responds to the read operation the values will be different. They may not be exactly as shown below but should look different to the values from when the card is not present.

With a CF card in the CF adapter

*i 10
00
*i 11
01
*i 12
01
*i 13
01


Without a CF card  in the CF adapter

*i 10
78
*i 11
78
*i 12
78
*i 13
78

[r4r...@gmail.com]

Hi, 

Okay, I tried those tests and this is the results I'm getting:  

Small Computer Monitor - SC114

*i 10
48
*i 11
49
*i 12
49
*i 13
49
*i 10
F8
*i 11
F8
*i 12
F8
*i 13
F8
*

[Steve Cousins]

It looks like the address decoding on the CF module is working. 

[r4r...@gmail.com]

Hi, 

Is there another command I should be using to format and copy CP/M to the CF card then? 

.

[r4r...@gmail.com]

Hi, 

Is it possible to use the two serial ports A and B on the Dual Serial v1.0 board at 9600 BAUD 8N1?  

.

[Steve Cousins]

Using SCM there is only the one method described, unless anyone has some alternative suggestions.

There are other methods of imaging CF cards on a PC or similar.

[Steve Cousins]

Port A of the RC2014 dual serial module takes its clock source from the CLK signal on the bus.

Port B of the RC2014 dual serial module takes its clock source from the CLK2 signal on the enhanced bus or from the CLK signal when only a standard bus is available (and JP1 shunt is fitted)

The SIO can be programmed with a very limited number of internal divider options but not enough to get 9600 baud from the typical 7.3728 MHz clock.

If you have the RC2014 dual clock module you can select a much slower clock for CLK2 and thus obtain low baud rates on port B. The module can also generate lower clock speeds for CLK but this will slow the processor down to about 600kHz (I think) if the serial port is to run at 9600 baud. When used with SC114 you would need to remove the oscillator from SC114 to avoid a conflict with the dual clock module.

You could physically modify the module to disconnect CLK as the port A clock source and feed CLK2 to port A as well as port B.

When used with SC114, which has standard 40 pin bus sockets, you can not use the CLK2 signal so your options are more limited.

[Mark T]

I think it would be possible to use one of the user pins on the 40 pin bus for clk2.

You could also get away with a simple 555 oscillator to generate a clock for 9600 baud. We used to use those with the 8251A in an 8085 system back in the day. You would need to trim the frequency to suit.

[Alan Cox]

This is what I made to do the job for various things I had

https://hackaday.io/project/168364-timer-retrofit-for-z80-sbcs

It's a single countdown IC and an input clock so easy to set up on a little bit of breadboard or similar.