Author Topic: Building a MicroMite Companion with a Propeller USB Proto Board  (Read 1223 times)

waltermixxx

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Howdy, I was wondering... I have 5 of these Demo Boards i purchased from the Propeller Powered Bargain basement a while back, and I would love to convert them to MicroMite companions.  :) I can put a socket on them for the Microchip, and use the build in PS/2 interface, but I was wondering what if any modifications would i need to do for VGA output?  :)    Has anyone home brewed one with one of these USB Proto Boards? :)   

( Hi Jeff,  I've been lurking in the land of Briel Retro computers lately, and the use of Propeller Chips has brought me back for a MicroMite Companion.   I wirewrapped a Replica 1Plus  (latest Apple 1 replica) and i purchased an Altair 8800micro)... :) made me appreciate the prop even more than before. :)

Cheers. :)

krs013

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Re: Building a MicroMite Companion with a Propeller USB Proto Board
« Reply #1 on: May 16, 2015, 12:45:04 AM »
Hey Walter

I don't pretend to know much about the MMC, and I don't have experience home brewing this board like you say, but I'd like to give you at least some response. My guess is that you could probably get this working without too much trouble. I seem to recall reading that the VGA circuit is borrowed from/based on a Parallax design--perhaps the Demo Board. It might need some pin reassignments at worst, but I think that the hardware should be in order for that.

I would think that the hardest part would be setting up the SD card, because the MMC needs that for basic functionality. If the available I/O pins on the DB can serve as the SPI bus for the SD card, you have a good chance at this.

The Propeller side of the MMC can operate quite well without the Microchip side (Micromite) so much as installed, at least well enough to boot up and display the startup screen. Perhaps you can program the Propeller and give it the SD card and see if that works before worrying about the Micromite!

Good luck

mindrobots

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Re: Building a MicroMite Companion with a Propeller USB Proto Board
« Reply #2 on: May 16, 2015, 07:55:29 PM »
Hi Walter,

Things around here are kind of quiet. Sorry your post went unanswered for so long.

The good news is you can build the PMC/PEB and MMC from almost ANY propeller board!

I built this one from an FPGA and a number of the Parallax component breadboard parts (VGA, uSD, PS/2 Keyboard). Retrobits (I think) built an MMC on the Parallax Professional Developer board. Search the forum for 'franken'

The circuits are all pretty standard and can be built on a protoboard or a breadboard based on the Parallax reference board schematics or teh schematics for teh PMC or PEB or MMC.

Parallax offers:

SD Card Adapter Kit
Protoboard Accessory Kit - PS/2 keyboard, mouse and VGA
VGA SIP Adapter Board
PS/2 to Breadboard Adapter
Micro SD Card Adapter

and maybe some I missed.

All the pieces are available to build what you need on one of your Proto boards,or a breadboard, or just about anything else!

Without the MMC, you have built a PMC or a PEB which are both fun and useful projects in their own right!

Ask, somebody will answer.......eventually!!  :D

waltermixxx

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Re: Building a MicroMite Companion with a Propeller USB Proto Board
« Reply #3 on: September 15, 2015, 10:57:54 PM »
Ok so i started to build my own MicroMite Companion.
I followed the instructions on the instructable, however,
i could not find which pins i use for Audio.

I am using the Propeller Proto USB, which has the necessary hardware for VGA, and PS/2 Keyboard. as well as the built in prop plug.
I added the 470ohm resister, and will add the 120ohm resisters from R-B-G to ground.

the Instructable, also indicates using P12 and P13 for serial communications,   but else where in the instructable, it lists using 12,13, 14 if you want TV out...

is it possible to get a schematic of the MicroMite Companion and a list of used prop pins? :)
it would help a great deal :)

Cheers. :)

attached is a picture of the board thus far, I have the SDcard accessible from the side I will be using case mounted PS/2 and VGA connectors.   Just wondering where to get audio from... :)

also can i use a standard 47uf capacitor?  i dont think i have ever seen a 47uf cap in ceramic... tantalum sure, but not ceramic... I have a run of the mill "little can" type capacitor of 47uf and was hoping i could use that... but at this point i am at  a stand still until i can sort out the audio. and perhaps get a schematic. :)


« Last Edit: September 15, 2015, 11:01:15 PM by waltermixxx »

blittled

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Re: Building a MicroMite Companion with a Propeller USB Proto Board
« Reply #4 on: September 17, 2015, 03:10:56 PM »
Walter, I posted a link to this page on http://electronicshobby.net/forums/viewtopic. php?f=2&t=13. This forum is hosted by Roadster who designed the PCB for the MMC so he may be able to help. This weekend I'll be on on the Propeller Powered chat with Roger and mindrobots who were active with the MMC and I'll let them know your questions. I'll be busy until the weekend, then I'll look at my MMC. In the meantime the Propeller code for the MMC may help you determine where things are connected.
« Last Edit: September 17, 2015, 04:34:11 PM by blittled »

waltermixxx

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Re: Building a MicroMite Companion with a Propeller USB Proto Board
« Reply #5 on: June 12, 2016, 08:16:04 PM »
Thanks... I'm thinking of working on this again some time soon, thank you for all the information and links. :)

I've been knee deep in COSMAC VIP and S100 stuff  :)  i will pick this up again sometime soon :)

cheers. :)