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My Web Site:

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


Here were a few thoughts and scribbles.

midi lead midi lead


Welcome to my wiki.

Doug's Wiki

This page contains random thoughts not fully thought out.

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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

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

My attempt to get a javaScript version running in a web browser


see: https://github.com/doug-h-rice for an emulator that used SDL for the screen and keyboard. There is also a java version. Also a PC version that builds using Tiny C.


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.

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.


Once again eBay suggested I buy a DigiSpark. 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 DigiSpark to Arduino IDE.


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

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

In the box labeled "Additional Boards Manager URLs" enter: http://digistump.com/package_digistump_index.json

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 needed to automate typing a conversation. I could use two and use the LED and input to handshake, so both were not typing over each other.


     | pause     | typing |GA| PAUSE        | typing |GA| PAUSE        
     | typing |GA| PAUSE     | typing    |GA| PAUSE     | typing           
  Turn on LED 
  LED| off       | On        |  off         | on        | Off
  LED| on        | off       |  on          | off       | On

This web page tries out this idea: http://www.dougrice.plus.com/dev/DigiSpark/text2.html

In the End having one as master and the other as slave worked best.

The AtoD also offers options to select what it does.

It is important to be able to disable the typing when plugged in.


Have a look at: http://www.dougrice.plus.com/Erlangs/adsl.htm

ADSL Home Hub NAT Sessions

During Covid working from home I can poll my Home hub to check out the NAT sessions.

We wanted t see what connections a Mobile Phone app made during the call.


Ideas that are still being thought through.

Multidimensional entity relationship diagrams Multidimensional entity relationship diagrams.

Complex base numbers Complex base numbers.

MISS Managing Insitutions that Sub Sample


twos compliment twos compliment numbers

Wet String Theory

[state space]?


function calls

integration and feedback

integration and feedback2


Dead Band Schmitt Trigger - Schmitt Trigger with LOW,OK,HIGH output and hysterisis

hand shakes




System Actions

The UseModWiki Actions, presented so that it's easy to copy to your own site. Each of these is implemented using "Local:" InterWiki interwiki links. (InterWiki links that start with "Local:" always point to the current wiki. See InterWikiDocumentation for more information on InterWiki links.






(The following links use this page for example, but id can equal any page. )


Don't forget the batteries

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Last edited April 21, 2021 9:26 pm by dougrice.plus.com