Looking for proven or "standard" dual Propeller circuit schematics

WBA Consulting

While working on my DipTrace skills, I am making tweaks to the Quickstart board for other needs on this thread. One suggestion is to make a dual propeller setup in the Quickstart form factor. However, I have no experience with dual prop setups, so I am looking for schematics that have been proven or meet the needs for users of dual prop layouts.

MacTuxLin

Mine worked with Beau's HS Prop-2-Prop. With such close proximity, I only needed 1 in-line resistors in each trace between the props.

prof_braino

Same with propforth, one 220 ohm resistor is in line between the two pins just in case somebody accidentally drives one pin high and the other low.
This works for both synchronous serial at full speed and async serial up to and a little above 230400 baud.

We found that when we are sure one prop will be an input pin and the other prop will be an output pin, the resistor is not needed.
But when code is changing, the resistor it always part of the testbed.

Also the writes between props are several inches long, just so we test with worst case.

WBA Consulting

Thanks for the replies! That covers pin to pin connections, but which pins should be connected? And what does the second prop need?

I was looking at Bill Henning's Morpheus' web page and it states "4 bit bus to CPU #1 on P28-P31". Is that the only thing needed for dual prop usage? Or is Morpheus setup for a specific type of dual prop usage? And he lists the EEPROM for the second prop as optional since the first prop would load it.

MacTuxLin

It probably depends on what your objectives are for this new board of yours (is it for your new dual-prop QS design?). I had a more specific requirements for my dual-prop1 board. And, I've read somewhere that the lower pins (P0~) are faster than higher ones (P24~). So, in my case, inter-props are comm with P0 & P1. Yes, unless you need a 2nd EEPROM for your 2nd prop, you can just load the 2nd prop from 1st prop via bootloaders, uSD loader or etc. And, as for crystal, you can drive your 2nd prop using the Sync object or an independent crystal set-up.

WBA Consulting

Thanks, that makes a little more sense as to why I can't find a ton of "standard" dual prop circuits. Yes, this is for my QS toying within DipTrace. It seemed like a dual prop layout in QS form factor would be desired by the community, but with caveats among users, a "standard" PCB layout may not be easily possible. Once I complete my learning of the schematic application, I will make a decision on what I will throw down in the empty space.

mindrobots

In the PropForth world, I've done multiplepropellers 2 ways.

1) using just bare propellers with decoupling but no crystal or EEPROM as the slaves, the master requires 6 pins to drive the slave. They are connected to pins 28-31 on the slave to provide EEPROM emulation (28&29) and serial I/O on 30 and 31. The other two provide clock and reset. The master prop will drive the slave's clock with a counter and drive reset when needed. It will also act as an EEPROM when the slave loads. You could also use a boot loader with this configuration.

2) using propellers with crystal and EEPROM as the slaves (or peers in this case), you just need a pair of pins between the two usually going to pin 30 and 31 on the downstream propeller to aid in booting. Standard serial I/O between them (or high speed multichannel).

I haven't done multi-prop with other languages yet.