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Re: ECB-DMA [message #8786 is a reply to message #8760]

Wed, 07 July 2021 03:27

lynchaj
Messages: 1080
Registered: June 2016

Senior Member

Hi Phillip
Awesome, this is great work and I am looking forward to robust testing of the new DMA board design. I would very much like to port the design over to the Z80 MBC and my plan is the DMA will be the next board after the Z80 FDC. Speaking of Z80 FDC, I am designing the Z80 FDC to be PIO and DMA compatible with the important DMA signals (TEND# and FDC_DMA) being exported as "flying signals" over-the-top. The Z80 DMA board will be an adaptation of the ECB-DMA board with a corresponding connector.

Probably this is not the greatest DMA-FDC design ever but the goal is to demonstrate it working and if successful we can make further adaptations in the inevitable PCB respin cycle. There are already a bunch of DMA related signals in the Z80 FDC design so I am hoping everything is covered. If someone is knows more about DMA and FDCs would please take a look at these features of the Z80 FDC and also the ECB-DMA and post feedback or send me an email.

Again, this is wonderful and its great to see this DMA issue finally getting its due after literally years of discussion. Great job and keep going!

Thanks, Andrew Lynch

PS, oh yeah, what I originally meant to say is these complicated direction logic circuits can drive you nuts trying to figure them out and get it straight. For me it was the bus direction on the original Z80 SBC with all the rules for internal and external IO, memory, etc. More recently, on the Z80 MBC it has been the chip select logic on the Z80 ROM and Z80 RAM were an odd combination that even on two separate boards had to work together. What I did was write up logic truth tables in my notes to get all the scenarios straight and ensure the outcome is what I was expecting and wanted to happen. Actually on the Z80 ROM and Z80 RAM boards I ended up putting the truth tables on the schematics because it was so difficult to explain how those two boards interact. You might consider a similar approach to make your design logic more visible and enable others to help you. Just a thought meant to help

[Updated on: Wed, 07 July 2021 03:34]

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[Message index]

		ECB-DMA By: b1ackmai1er on Sun, 10 November 2019 00:16
		Re: ECB-DMA By: Wayne W on Tue, 12 November 2019 12:31
		Re: ECB-DMA By: jcoffman on Tue, 12 November 2019 16:14
		Re: ECB-DMA By: etchedpixels on Wed, 13 November 2019 15:40
		Re: ECB-DMA By: b1ackmai1er on Fri, 15 November 2019 20:34
		Re: ECB-DMA By: b1ackmai1er on Sat, 16 November 2019 04:56
		Re: ECB-DMA By: etchedpixels on Sat, 16 November 2019 05:23
		Re: ECB-DMA By: jcoffman on Sat, 16 November 2019 08:03
		Re: ECB-DMA By: wsm on Sat, 16 November 2019 09:28
		Re: ECB-DMA By: jcoffman on Sat, 16 November 2019 13:09
		Re: ECB-DMA By: wsm on Sat, 16 November 2019 14:02
		Re: ECB-DMA By: b1ackmai1er on Sun, 17 November 2019 05:50
		Re: ECB-DMA By: jcoffman on Sun, 17 November 2019 07:06
		Re: ECB-DMA By: etchedpixels on Sun, 17 November 2019 07:41
		Re: ECB-DMA By: wsm on Sun, 17 November 2019 10:06
		Re: ECB-DMA By: wsm on Sun, 17 November 2019 14:12
		Re: ECB-DMA By: jcoffman on Sun, 17 November 2019 21:28
		Re: ECB-DMA By: rcini on Thu, 12 December 2019 17:52
		Re: ECB-DMA By: wsm on Thu, 12 December 2019 21:24
		Re: ECB-DMA By: rcini on Fri, 13 December 2019 07:22
		Re: ECB-DMA By: mikesmith on Thu, 09 January 2020 18:36
		Re: ECB-DMA By: wsm on Thu, 09 January 2020 20:28
		Re: ECB-DMA By: lynchaj on Mon, 26 April 2021 09:03
		Re: ECB-DMA By: lynchaj on Tue, 27 April 2021 04:41
		Re: ECB-DMA By: lynchaj on Wed, 28 April 2021 08:00
		Re: ECB-DMA By: jcoffman on Sat, 16 November 2019 07:56
		Re: ECB-DMA By: jcoffman on Sat, 16 November 2019 07:45
		Re: ECB-DMA By: b1ackmai1er on Thu, 17 June 2021 07:14
		Re: ECB-DMA By: lynchaj on Thu, 17 June 2021 07:29
		Re: ECB-DMA By: b1ackmai1er on Sat, 19 June 2021 05:33
		Re: ECB-DMA By: lynchaj on Sat, 19 June 2021 07:11
		Re: ECB-DMA By: lynchaj on Sat, 19 June 2021 07:30
		Re: ECB-DMA By: b1ackmai1er on Mon, 21 June 2021 07:31
		Re: ECB-DMA By: b1ackmai1er on Sat, 26 June 2021 19:10
		Re: ECB-DMA By: b1ackmai1er on Fri, 02 July 2021 02:06
		Re: ECB-DMA By: lynchaj on Fri, 02 July 2021 04:49
		Re: ECB-DMA By: b1ackmai1er on Fri, 02 July 2021 07:23
		Re: ECB-DMA By: etchedpixels on Thu, 08 July 2021 08:22
		Re: ECB-DMA By: b1ackmai1er on Fri, 09 July 2021 22:08
		Re: ECB-DMA By: lynchaj on Tue, 13 July 2021 11:44
		Re: ECB-DMA By: lynchaj on Thu, 29 July 2021 12:15
		Re: ECB-DMA By: b1ackmai1er on Sun, 04 July 2021 08:09
		Re: ECB-DMA By: b1ackmai1er on Mon, 05 July 2021 07:35
		Re: ECB-DMA By: lynchaj on Wed, 07 July 2021 03:27
		Re: ECB-DMA By: lynchaj on Wed, 07 July 2021 03:44
		Re: ECB-DMA By: lynchaj on Mon, 14 March 2022 03:48
		Re: ECB-DMA By: lynchaj on Wed, 23 March 2022 10:05

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