Search found 82 matches
- 24 Nov 2018 19:42
- Forum: SOFTWARE
- Topic: New tape cleaner tool
- Replies: 59
- Views: 90094
Re: New tape cleaner tool
What would be read? In normal operation an interrupt is triggered on an edge (can't remember which on). Would not the bit read just reflect if an edge has been detected or not? As an aside, one of these days, when the emulators are up to it, I would love to write a tape loader with music and loadin...
- 19 Nov 2018 22:27
- Forum: SOFTWARE
- Topic: New tape cleaner tool
- Replies: 59
- Views: 90094
Re: New tape cleaner tool
Does the CTC set a register that can be polled? Yes, here is an extract from the Zilog Z80 Family User Manual: The Down-Counter The down-counter is an 8-bit register that is used in both COUNTER and TIMER modes. This register is loaded by the Time Constant register both initially, and when it count...
- 19 Nov 2018 15:47
- Forum: GENERAL DISCUSSIONS
- Topic: Problems with Ads on Memorum?
- Replies: 13
- Views: 14142
Re: Problems with Ads on Memorum?
The offending lines in the forum code are: <!-- Begin BidVertiser code --> <SCRIPT data-cfasync="false" SRC="//bdv.bidvertiser.com/BidVertiser.dbm?pid=824774&bid=1967045" TYPE="text/javascript"></SCRIPT> <!-- End BidVertiser code --> The imported javascript could b...
- 19 Nov 2018 01:10
- Forum: SOFTWARE
- Topic: New tape cleaner tool
- Replies: 59
- Views: 90094
- 18 Nov 2018 22:23
- Forum: SOFTWARE
- Topic: New tape cleaner tool
- Replies: 59
- Views: 90094
Re: New tape cleaner tool
A tape-related conundrum for you: The MTX is interesting because the cassette input is via the CTC, which can be configured with this code: LD C,0BH ;CTC channel 3 port LD B,0C5H ;Enable interrupt, counter mode, trigger on C/T3 falling edge LD A,1 ;Time constant = 1 OUT (C),B OUT (C),A Could there b...
- 27 Oct 2018 14:41
- Forum: SOFTWARE
- Topic: Thoughts on Einstien "Stolen" Software?
- Replies: 5
- Views: 6918
Re: Thoughts on Einstien "Stolen" Software?
Mark, it was taken aback but once I realised there was a solution it didn't take very long. All done the same day, I think.
Instead of one of C/T0, C/T1 or C/T2 tied to /VDPINT they are all connected to 2 MHz - a strange design decision.
Instead of one of C/T0, C/T1 or C/T2 tied to /VDPINT they are all connected to 2 MHz - a strange design decision.
- 19 Oct 2018 16:17
- Forum: SOFTWARE
- Topic: Thoughts on Einstien "Stolen" Software?
- Replies: 5
- Views: 6918
Re: Thoughts on Einstien "Stolen" Software?
The Einstein VDP /INT is not connected to Z80 /INT or /NMI or anything else. I couldn't believe it when I found out and therefore converting the Speculator was not as simple as it should have been. Luckily CTC channels 2 and 3 can be cascaded (ZC2 tied to C/T3) and I programmed channel 2 in timer mo...
- 19 Oct 2018 15:10
- Forum: HARDWARE
- Topic: NTSC/PAL VDP setup?
- Replies: 11
- Views: 12005
Re: NTSC/PAL VDP setup?
The VDP datasheet says: Note: Enabling bit 7 (actually bit 0/LSB) in the TMS9928A/9929A causes A-Y and B-Y to go to the sync level only when all planes in front of the pixel under question are transparent. I have no idea what they mean by this. A-Y is an error and should be R-Y . More from the data...
- 03 Oct 2018 15:37
- Forum: SOFTWARE
- Topic: Thoughts on Einstien "Stolen" Software?
- Replies: 5
- Views: 6918
Re: Thoughts on Einstien "Stolen" Software?
A diskette was sold that allowed some extra Spectrum games to run on the Einstein Speculator which I knew nothing about at the time, despite it being my device. The Einstein had an interesting hardware "feature" - the VDP /INT pin was not connected to anything! I met the chief designer dur...
- 06 May 2018 22:04
- Forum: NEW HARDWARE
- Topic: Rodents anyone ?
- Replies: 17
- Views: 18289
Re: Rodents anyone ?
What if the CP/M BIOS set up a frequent interrupt to read the mouse keys?