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Rev 1 Arrival and some chips

A project log for Basic MC6800

Building a simple striped down computer from the mid 70's based around the Motorola MC6809 MPU

Gee BartlettGee Bartlett 03/29/2020 at 11:373 Comments

I always feels nice to receive a PCB you have designed.

Even though I know that there is a problem with the ROM and peripheral selector on this board i feels good in the had and should give me enough to work with at least to see it running. 

Really pleased with how the silk looks, by the way the bin is ASCII (nerdy i know) :)

another nice arrival was the Processors themselves surprised about the date code week 22 2018 so reasonably new chips  looking in great and unused condition. I am hopeful for these i need something to set the free running though.

Discussions

Steve Toner wrote 03/31/2020 at 00:03 point

Motorola spun off its microprocessor business as Freescale Semiconductor in 2004.  Therefore, what you have are remarked chips that are either not made by Motorola, not made in 2018, or both.  Rochester Electronics is licensed to make new ones (since 2015), but those would not have a Motorola logo and are not cheap.  I wouldn't trust them to be later mask sets either (see note in datasheet about MRDY input)...

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Gee Bartlett wrote 03/31/2020 at 09:19 point

Thanks for the heads-up :) I did have a look to  see if they have some weird way of date coding but couldn't find anything in the datasheet. I have only managed to set one of these free running so far so you could be right. I'll have to see if any has new old stock.

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Steve Toner wrote 03/31/2020 at 14:47 point

I've had good luck with this vendor: https://www.twistywristarcade.com/processors-40-pin-ics/595-6809-mpu.html?search_query=6809&results=4

(and ceramic packages add to the cool factor :-)

The ones you have will probably work, but it's always good to have a known good part if there's a problem and you want to know if it's your fault or a dodgy chip...

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