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Re: A simple CP/M Z80 SBC without glue logic [message #6147 is a reply to message #6146]

Fri, 15 March 2019 09:39

etchedpixels
Messages: 333
Registered: October 2015

Senior Member

wsm: agreed - the reason for wiring it to A15 is it means you can then attach other stuff to it later, otherwise you are constrained to the single KIO, whereas if you wire it to A15, fit an optional RC2014 connector and wire the IRQ line from the RC2014 to a PIO pin you get *all* of the RC2014 I/O features including being able to manage the RC2014 interrupt line in IM2 mode for free (more than most RC2014 CPU cards can do! Wink

. Come to think of it if you decided to pull the RAM and ROM chips I think you get all of RC2014 later if you wanted ?

Extra RAM looks more awkward though - the 512K RAMs seem to drop CE2.

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[Message index]

		A simple CP/M Z80 SBC without glue logic By: plasmo on Thu, 14 March 2019 08:20
		Re: A simple CP/M Z80 SBC without glue logic By: wsm on Thu, 14 March 2019 10:50
		Re: A simple CP/M Z80 SBC without glue logic By: plasmo on Thu, 14 March 2019 11:09
		Re: A simple CP/M Z80 SBC without glue logic By: mikemac on Thu, 14 March 2019 16:39
		Re: A simple CP/M Z80 SBC without glue logic By: wsm on Thu, 14 March 2019 18:01
		Re: A simple CP/M Z80 SBC without glue logic By: etchedpixels on Fri, 15 March 2019 05:21
		Re: A simple CP/M Z80 SBC without glue logic By: wsm on Fri, 15 March 2019 08:47
		Re: A simple CP/M Z80 SBC without glue logic By: plasmo on Fri, 15 March 2019 09:11
		Re: A simple CP/M Z80 SBC without glue logic By: etchedpixels on Fri, 15 March 2019 09:39
		Re: A simple CP/M Z80 SBC without glue logic By: wsm on Fri, 15 March 2019 10:15
		Re: A simple CP/M Z80 SBC without glue logic By: plasmo on Sat, 16 March 2019 06:41
		Re: A simple CP/M Z80 SBC without glue logic By: plasmo on Thu, 04 April 2019 05:34
		Re: A simple CP/M Z80 SBC without glue logic By: b1ackmai1er on Thu, 04 April 2019 06:29
		Re: A simple CP/M Z80 SBC without glue logic By: plasmo on Thu, 04 April 2019 07:28
		Re: A simple CP/M Z80 SBC without glue logic By: etchedpixels on Thu, 04 April 2019 09:56
		Re: A simple CP/M Z80 SBC without glue logic By: plasmo on Thu, 04 April 2019 13:58
		Re: A simple CP/M Z80 SBC without glue logic By: wsm on Thu, 04 April 2019 14:42
		Re: A simple CP/M Z80 SBC without glue logic By: plasmo on Thu, 04 April 2019 18:19
		Re: A simple CP/M Z80 SBC without glue logic By: wsm on Thu, 04 April 2019 19:10
		Re: A simple CP/M Z80 SBC without glue logic By: etchedpixels on Fri, 05 April 2019 03:34
		Re: A simple CP/M Z80 SBC without glue logic By: plasmo on Fri, 05 April 2019 05:44
		Re: A simple CP/M Z80 SBC without glue logic By: etchedpixels on Thu, 04 April 2019 09:49
		Re: A simple CP/M Z80 SBC without glue logic By: plasmo on Fri, 15 March 2019 09:03

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