Retro Challenge update #6

Yesterday was our king‘s birthday and everything stops, including delivery services. The PCB and components I needed for the HD6309 computer still hadn’t turned up. I did have tracking available on both packages, but until the last minute, they kept showing May 1st. Luckily, this afternoon, both packages arrived!

I quickly assembled the board. It went well, except for soldering the 12MHz CPU oscillator; I ordered the wrong package :-/ — it’s a lot smaller than the 7x5mm footprint I used. The UART has a 7+ MHz oscillator with 7x5mm footprint so I think I’ll use that.

After assembling the board, the first thing I checked is that there were no shorts. Without fitting the CPU, EPROM and GALs, I applied 5V to the board. Setting a very low current limit is advisable to save components from releasing their magic smoke. The current meter on my power supply is an old analogue one with a bent needle; I estimate the current to be around 20 mA. This is to be expected as there is a power LED:

hd6309_computer_pcb_28_4_2017

So far so good!

Next up…

I have the programming files for the memory decoder GAL done. I need to create the IO decoder GAL files, create a few additiona test programs, and adapt the bootloader I showed previously to use the SCC16C550 UART.

Lots to do, so little time!

 

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