RC 2014 Pro assembly - Need advice

[Scott Burton]

I have soldered together a RC 2014 Pro kit and too no big surprise it does not work.  I am a novice electronics hobbyist and want to get into homebrew computing. I have started to troubleshoot it by doing continuity\short circuit testing with a multimeter and following the advice from https://rc2014.co.uk/troubleshooting/.  My soldering looks ok and is a lot better since I got a '998D 2 in 1 Soldering Station' from ebay.  

I have found a 40-pin ZIF socket in my collection of stuff and decided to try and fit it to the 'Z80 V2.1' board because I have already bent and stressed the CPU pin legs so much that if they are bent out of place again some will surely snap off.  I have removed the regular DIP socket with a soldering hot air gun, removed the solder covering the 40 pin holes with a solder sucker.  Then I found out the ZIF socket has wider pins that are too big for the PCB .  A regular 40-pin DIP socket can fit fine.  How can I fit the ZIF socket to the board.  Is there a intermediate socket I can put in-between the PCB and the ZIF socket?

My 2nd question is with a ROM chip that is marked '4006000' what jumper settings should I set on:

   ROM board:  A13, A14, A15 and 'Page Size Jumper Selection; - 5 jumpers

   RAM board:  Start address (hex) - 4 jumpers.

Thanks for the help.

[Scott Burton]

The 2nd question - Jumper settings so the RC2014 Pro can boot into BASIC.for 56K RAM.

[Mark Ericksen]

On Saturday, December 30, 2017 at 2:39:46 AM UTC-5, Scott Burton wrote:

I believe that your ROM label should read 40006000 for a total of 8 digits and not 7 (4006000) as shown in your message.

That ROM is a 64K ROM divided into eight 8K pages.  The page size jumpers should be set from left to right as down - down - up - up - up.

 

That ROM is a 64K ROM.  The 4 in the first position on the label tells me that 57K BASIC for the SIO/2 serial card is in the first 8K block.  The starting address for the 8k block is 0x0000, and that makes sense because the Z80 is going to access 0x0000 for its first instruction upon a RESET.  Due to the ROM board design every 8K block on the ROM IC will start at 0x0000 when that 8K page is selected.  The jumpers on the ROM board serve two functions: 1 - to specify the size of the ROM blocks (8K in this case), and 2 - to specify which ROM block is selected.

Remember that because you have an 8K of Read Only Memory residing at 0x0000 the RAM address space must start at 0x2000, so the RAM board must be configured accordingly.  From top down on the RAM board the jumpers are Right - Left - Left -Left.  This specifies that RAM begins at 0x2000, one memory location beyond the ROM address space.  On the RAM board you will see graphics by the jumper blocks that look like this: " - - . " and that means that the jumper runs from the left position to the center position with the right most pin not connected to anything.

The 6 is in the in what I believe is the fifth position on the label.  That 8K block contains the CP/M boot loader.  It will be located at 0x000 but will copy itself into RAM and the switch out all ROM and switch in all 64K of RAM (bank switching).  The ROM board and RAM board will have to be reconfigured to do this and you will need the compact flash board with a compact flash card that has CP/M on it (correct version for your serial card is needed) .

I hope this information helps, and if anyone reads this and finds an error please correct the information.  You won't hurt my feelings.

Mark Ericksen, AD4MA

Clearwater, Florida

 

[Scott Burton]

See the attached image that shows my ROM chip has '(strange character) 40 06000' printed on it.

At this point I would be happy just to get the RC 2014 to boot into BASIC.  I have the compact flash board and a 128 MB CF card labelled as '128MB SIO/2'.  

On the Clock board I have only soldering on components that are inside the left most white border with a single jumper on '7.3728'.  From what I have read this should be ok with on the Dual Serial 1.0 board a jumper is on 'Port B Clock'.

I am using a cheap CP2102 USB to Serial adapter to connect to 'Port A' on the serial board.  It works fine with a Orange Pi Zero single board computer but from reading another post in this discussion group the cheap USB to Serial adapters are unreliable.  I have ordered a couple of different USB FTDI Serial adapters.

After using a soldering hot air gun for the first time on the Z80 CPU 2.1 board I have basically ruined it because some a lot of the pin header to 40-pin DIP connections are now broken.  I have ordered a replacement board.kit.

I am learning new stuff and hopefully I will have a working RC 2014 'soon'.  I will get a USB Hantek Oscilloscope to help my troubleshooting.

[Steve Cousins]

Hi Scott

I think the ROM label should read 24006000.

This is the only matching ROM image at https://github.com/RC2014Z80/RC2014/tree/master/ROMs/Factory.

From info at https://rc2014.co.uk/1515/decoding-rom-labels/ this would mean:

2 – Microsoft BASIC, for 32k RAM, SIO/2, with origin 0x0000

4 – Microsoft BASIC, for 56k RAM, SIO/2, with origin 0x0000

0 – Empty bank, available for user to program

0 – Empty bank, available for user to program

6 – CP/M Monitor, for pageable ROM, 64k RAM, SIO/2, CF Module at 0x10, with origin at 0x0000

0 – Empty bank, available for user to program

0 – Empty bank, available for user to program

0 – Empty bank, available for user to program

I have similar kit to you but can't easily check above as my system is currently configured differently. But from memory I think it is correct.

I'd start to debug the system by only including the essential modules CPU, Clock, RAM, ROM and set the ROM jumpers to run the Microsoft BASIC, for 32k RAM, SIO/2, with origin 0x0000. So ROM board links A15=0, A14=0, A13=0.

This thread may be worth a read: Pageable rom and 64k ram jumper positions

Steve

[Spencer Owen]

On 31 December 2017 at 04:22, Scott Burton <scott....@gmail.com> wrote:

See the attached image that shows my ROM chip has '(strange character) 40 06000' printed on it.

Just a quick explanation of the "strange character"; Despite having free reign to come up with a labeling scheme of whatever I wanted, I managed to choose a combination that my label machine was unable to produce!  The strange character is an interlinked n and u, which is the closes thing on that reel that represents a 2.

However, I have now bought a couple of new label guns and after stripping them right down and swapping the reels about, I can now print "2400600" labels :-)

  

Cheers

Spencer

[David Lee]

Thank for clarifying this Spencer. It was very confusing for me when I was just getting started with the kit. Might I suggest you add this as an errata to http://rc2014.co.uk/1515/decoding-rom-labels/ ?

[Spencer Owen]

Hi David,

Yes, I should do.  There's a few updates the website needs, which hopefully I'll sort out later this week.

Cheers

Spencer

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