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Doug's Wiki

Welcome to my wiki. Here were a few thoughts and scribbles. This page contains random thoughts not fully thought out.

My Web Site:


My github: https://github.com/doug-h-rice


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thoughts and scribbles

Here were a few other thoughts and scribbles. This page contains some random thoughts not fully thought out.

thoughts and scribbles

ADSL Home Hub NAT Sessions

AutoType Using an Arduino Leonardo and DigiSpark as a keyboard and type.

AT Commands - Serial Using Web Browser - Cloud based IDE still need to upload firmware to devices. Web Browser support serial devices.

Signalling - After a visit or two to the local heritage railways.

Wet String Theory - essential thoughts and Array of JavaScript Objects

WetString - brainstorm ideas about Peer to Peer

Old Computer projects and dabbles


I used to have a Science of Cambridge MK14 and a NASCOM 2. Here are some notes.

MK14 notes

MK14 KarenOrton pictures - site with good documentation.

My attempt to get a javaScript version running in a web browser, with lots of cheats:-


https://github.com/doug-h-rice My git hub has MK14 emulators that used SDL for the screen and keyboard. There is also a java version. Also a PC version that builds using Tiny C.


My second computer was the NASCOM 2. When I brought it the 8K RAM chips could not be sourced, so it came with a dymanic RAM board. I piggy backed a set of RAM chips on top to double the RAM. I had at least 32K RAM.

I also used a second hand 8 inch floppy brought from Display Electronics and WD1771 floppy disk controller chip. It could only read 80% of the tracks, but once you had command to read write multiple sectors, it was better than a tape. The DOS was a bit of Paper. Later on it was on the disk. I added a 6116 2K memory chip and NiCad Battery to save the code.

I bought a Golfball printer. It could be controlled using the PIO chip. It was controlled using a 2 x 7 solenoids and a busy output. These needed 50 volts. I needed a big thick bit of sorbo rubber to stop the vibrations being heard all around the hall of residence! It took 4 minutes to type a page of A4.

Nascom 2 Notes

Multicomp minimal component microprocessors

Grant Searle has published some designs for minimal component microprocessor boards that run Microsoft BASIC.


Minimal component Z80,6502,6809 boards are popular. He has an FPGA version.

My Minimal component Z80 emulator system based on Grant's multicomp. https://github.com/doug-h-rice/virtual-multicomp

Multicomp reworks and Tribute sites

Grant's website havs spawned many projects


This one is useful. Doug has ported Grants code to many FPGA boards.

It seems to be under a tidy up ( April 2020 )

6809 - Grant Searle's Multicomp FPGA

I remember somebody at the Coventry computer club being enthusiastic about the 6809 in 1979. Here are some notes about getting some assembler code into an FPGA

My Notes on 6809

The emulated CPU communicates with the host using the UART.

This is summarised as a TX and RX register and two flags TxEmpty and RxFull.

Emulated CPU - UART:-

  A write to TX resets TxEmpty.
  A read from RX resets RxFull.

UART - Host:-

  A read from TX sets TxEmpty.
  A write to RX sets RxFull.

If you have a FIFO then there need to be changes.

 TxEmpty may need to be TxSpaceAvailable 
 RxFull becomes RxAvailable

RC2014 Z80 SBC

Spencer Owen's Z80 system similar to multicomp. https://rc2014.co.uk/

Small Computer Monitor by Stephen C Cousins ( www.scc.me.uk ) Version 1.0.0 configuration R1 for Z80 based RC2014 systems


Version 1.0.0 configuration R1 for Z80 based RC2014 systems


In passing I found these. Raspberry Pi Bare Metal

https://ultibo.org/ https://ultibo.org/make/

Running CP/M on a Raspberry Pi Bare Metal.

This is good for old models of the PI that are slow with the later RPi builds.



8051 CY7C68013 EZ-USB FX2 USB 2.0 Development Kit Ebay suggested I buy one of these. I was looking for a microprocessor that did not boot from internal FLASH memory!



http://www.dougrice.plus.com/dev/cypress/i2c.c tries to write to the IIC 24LC128. The link may need moving to enable writing to the ROM.


I was given one of these: https://www.futurlec.com/USBDevBoard.shtml

It has been a challenge to get it to work.


 Getting FLIP to work is troublesome. 
 To put chip into boot mode, use this sequence.
 press reset, PSEN and release reset when PSEN pressed, then turn on USB switch.

 rem compile doug_at.c and uses dfu-programmer to program the chip.
 rem https://sourceforge.net/projects/dfu-programmer/

 sdcc -mmcs51 --std-c99  doug_at.c

use lsusb to see if in bootmode.


 You may need to use sudo otherwise you get device not present

 sudo dfu-programmer at89c5131 get
 sudo dfu-programmer at89c5131 erase
 sudo dfu-programmer at89c5131 flash doug_at.ihx
 sudo dfu-programmer at89c5131 launch

dhr.asm - first ATTTiny2313 program

Some Maplin kits used an Atmel Tiny 2313.

It is possible to add it to the Arduino IDE.

http://www.dougrice.plus.com/dev/dhr_avr/ has some pre Arduino tries.

Elector had an Avrdude example using a serial port and resistors.


Once again eBay suggested I buy some DigiSparks. At the price suggested, it was worth a go. They are super for HID keyboard automation. I have needed to reflash the bootloader once or twice.

Adding DigiSparks to Arduino IDE. See:- DigiSparks.


This is very helpful: http://digistump.com/wiki/digispark/tutorials/connecting

Drivers and firmware: https://github.com/micronucleus/micronucleus v2.04

I got this when using the board manager and Win10: "CRC error, file corrupted. Try to repeat later"

This helped. https://github.com/arduino/Arduino/issues/9719

I deleted C:\Users\doug\AppData\Local\Arduino15\library_index.json

When I next opened the IDE it seemed to have installed the new boards.


https://github.com/arduino/Arduino/issues/9719 - Win10 reports CRC error

I have updated my old ADSL2 hub as it was corrupting iPhone updated and the new hub seems to work.

ESP01 and IOT

ebay suggested the ESP01 and support to reprogram these has been added to the Arduino.

JavaScript prototypes for PIC projects

http://www.dougrice.plus.com/dev/sportstimer.htm - sports timer

http://www.dougrice.plus.com/dev/ratemultiplier.htm - JavaScript Rate Multiplier.

http://www.dougrice.plus.com/dev/pulseStretch.htm - measures input pulse and then outputs a pulse 5 times longer

http://www.dougrice.plus.com/dev/pulseStretch2.htm - Using leaky bucket to strech pulse 5 times longer


PIC projects

PIC 10F204 PIC10F204 random number generator.

PIC 16F88 driving IIC display PIC 16F88 driving IIC display

PIC 16F819 IIC/Serial demo with debug of SSPSTAT PIC 16F819 IIC / Serial demo with debug of SSPSTAT

Contact Bounce example Contact Bounce example

Raspberry Pi projects

pi config - notes on setting up my pi

plotting DS18S20 temperature readings using SVG

Arduino projects

Arduino Colordunio And SVG Projects

Arduino based logger and SVG Graph

System Actions

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Don't forget the batteries

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Last edited November 6, 2021 10:22 pm by dougrice.plus.com