Trying to interface a 6551 to my pc's serial port

[Dr Jefyll]

BigDumbDinosaur wrote:

GARTHWILSON wrote:

[...] I kept kidding them about a capacitor the size of a car [...]

Just think what it would take to charge it up.

If you had access to MegaFarad capacitors you could build a car -- a darn nice electric car! (assuming the cap's voltage rating is reasonable)

-- Jeff

[ioncannon]

Going to add into this post to avoid another thread. I am designing a expansion interface so I can put the stuff I have now (RAM, ROM, ACIA, and CPU) onto a pcb (co-worker has the tools to make one), and then I can add things to it w/o breaking the main board (wires popping out due to it being on a breadboard).

I will upload a drawn circuit later but this is how I planned it out:

-Address, Data, and Control buses, and clock out go into each exp port.
-There will be a control circuit that is enabled by the address decoder. The circuit consists of a latch and a demux. The latch controls the last set select line on the demux. Inputted into the demux is the EXPANSION_EN line from the address decoder, and each output goes to a expansion port.

So for example:

You want to access a RAM card on exp port 3.
SELECT_EN is at $5000
EXPANSON_EN is at $6000-$7FFF

You'd store a %00000010 into $5000 which set's the demux to line 3.

Now you can load and store memory from $6000-$7FFF. The EXPANSION_EN line get's activated by the decoder, and because of the demux, activates the third expansion line.

Hopefully I explain as clear as possible, as I said, will upload a circuit when I get home. Think it will work? This is pretty much banking right?

[BigEd]

I'd prefer a new thread, to be honest. It helps a lot when searching the forum at a later date - and it might be you, coming back to a project after a gap of months or even longer.

It does sound like banking, to me, and that can certainly be made to work.

Cheers
Ed