Home » RBC Forums » General Discussion » General Instrument CTS256A-AL2 vs. Microchip CTS256AL2
| Re: TMS7000 Series Devices (Manual section 2.1) [message #10655 is a reply to message #10650] |
Thu, 04 April 2024 04:59   |
lynchaj
Messages: 1080
Registered: June 2016
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Senior Member |
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Hi
I've got DAISY256 PCBs on the way and gathered up all the parts I have on hand for the project. Made some orders for the parts I am missing including 3 TMS7001NL-4 chips for initial testing. I think those are the most likely to work since they are the most closely similar to the PIC7041 that the CTS256 was derived from. The only difference being the lack of 4KB internal mask EPROM.
*IF* the TMS7001 works (that's a big IF), do you see anything preventing the TMS77C82 from working? I realize it has an 8KB internal EPROM but in microprocessor mode, that will be ignored so not really a difference. The TMS7xCx2 parts have some extra capabilities but if you don't use them, the CTS256 firmware should still work "as-is". Is that right? Or would the CTS256 firmware require modification?
I found some cheap TMS77C82 DIP40 chips on AliExpress so I ordered 3 to do some tests. Assuming I can get the TMS7001 parts to work, it should be just a simple swap with the TMS77C82 parts to test if they work. Probably could through a whole list of pin-compatible parts sorting out which ones work and which don't but only a couple of common chips (TMS7001 and TMS77C82) should be sufficient for the limited hobbyist demand for CTS256 replacements.
What do you think? Thanks
PS, I also ordered 5 TMS70C02 chips in DIP40 for about $13 from AliExpress. That's like $2.50 each shipped. I don't know if they will work but I think they have a reasonable chance. That's about 2% of the going rate on eBay where I routinely see CTS256s for >$100 each.
PPS, I think I've found another wrinkle in my plan. It turns out the divide by two or divide by 4 clock options are set in the mask at manufacturing. I am confident the CTS256 uses the /4 option since it requires a 10MHz crystal. However, other TMS7xxx use the /2 option and will need a 5MHz clock to get the same system performance. For a real time application like this, clock speed is super important so I recommend the crystal be socketed until we get this sorted out. I suspect the TMS7xCx2 parts will not work with a 10MHz crystal so make sure it is easy to replace. From the TMS7000 databook:
PPPS, this also clarifies the difference between TMS7001NL-2 and TMS7001NL-4. The -2 uses 5 MHz crystal and the -4 uses 10 MHz crystal. As long as the crystal is socketed, I am guessing either will work fine. This opens up more potentially suitable parts. I think the TMS7xCx2 parts all use /2 clocks (confirmed, paragraph 4.2.7 of TMS7000 databook, all TMS70Cxx use /2 only).
[Updated on: Thu, 04 April 2024 08:29] Report message to a moderator |
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General Instrument CTS256A-AL2 vs. Microchip CTS256AL2
By: lynchaj on Fri, 28 April 2023 03:28 |
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Re: General Instruments CTS256A-AL2 vs. Microchip CTS256AL2
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Re: General Instruments CTS256A-AL2 vs. Microchip CTS256AL2
By: scruss on Sat, 06 May 2023 16:46 |
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Re: General Instruments CTS256A-AL2 vs. Microchip CTS256AL2
By: lynchaj on Sat, 06 May 2023 18:13 |
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Re: github project may have extracted the CTS256A-AL2 code
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Re: General Instruments CTS256A-AL2 vs. Microchip CTS256AL2
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Re: Programming the Naval algorithm as a CTSx for PIC/TMS7000 or otherwise
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Re: General Instruments CTS256A-AL2 vs. Microchip CTS256AL2
By: lynchaj on Mon, 08 May 2023 04:04 |
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Re: Is the PIC/TMS7041 field programmable?
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Re: Is the PIC/TMS7041 field programmable?
By: lynchaj on Mon, 08 May 2023 12:50 |
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Re: No source of new-old CTS256A-AL2 economical micro solutions
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Re: No source of new-old CTS256A-AL2 economical micro solutions
By: lynchaj on Tue, 09 May 2023 04:41 |
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Re: No source of new-old CTS256A-AL2 economical micro solutions
By: scruss on Sun, 14 May 2023 09:40 |
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Re: No source of new-old CTS256A-AL2 economical micro solutions
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Re: No source of new-old CTS256A-AL2 economical micro solutions
By: scruss on Wed, 17 May 2023 07:11 |
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Re: No source of new-old CTS256A-AL2 economical micro solutions
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Emulating a TMS/PIC7000 (CTS256A-AL2) in a new MCU...
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CHAPTER 01 :: "Introduction to Hardware Emulation of the 7000 Series"
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Re: General Instruments CTS256A-AL2 vs. Microchip CTS256AL2
By: lynchaj on Mon, 25 March 2024 11:23 |
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Re: General Instruments CTS256A-AL2 vs. Microchip CTS256AL2
By: lynchaj on Wed, 27 March 2024 19:11 |
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Re: General Instruments CTS256A-AL2 vs. Microchip CTS256AL2
By: lynchaj on Sun, 31 March 2024 08:46 |
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7000 Series Unobtainium may be OBTAINium?
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Re: General Instruments CTS256A-AL2 vs. Microchip CTS256AL2
By: lynchaj on Sun, 31 March 2024 17:38 |
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Tables of Various 7000 Series Device Features/Specifications
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Re: TMS7000 Series Devices (Manual section 2.1)
By: lynchaj on Mon, 01 April 2024 12:01 |
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Prototyping 7xxx Devices appear to support External Memory?!
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Re: TMS7000 Series Devices (Manual section 2.1)
By: lynchaj on Wed, 03 April 2024 03:57 |
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Re: TMS7000 Series Devices (Manual section 2.1)
By: lynchaj on Thu, 04 April 2024 04:59 |
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CTS256 resurrection from old 70xx & SP-0256* too?!
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Re: TMS7000 Series Devices (Manual section 2.1)
By: lynchaj on Thu, 04 April 2024 10:00 |
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70x1 Memory Access Timing: Internal -versus- External Access
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Re: 70x1 Memory Access Timing: Internal -versus- External Access
By: lynchaj on Fri, 05 April 2024 06:07 |
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TMS7000 Series with Custom Micro-Coded Instructions
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Re: TMS7000 Series with Custom Micro-Coded Instructions
By: lynchaj on Sat, 06 April 2024 16:52 |
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Daisy 256 & the Speech Processor
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Re: Daisy 256 & the Speech Processor
By: lynchaj on Sun, 07 April 2024 07:08 |
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Reverse-Engineering the Speech Processor ROM
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Re: Reverse-Engineering the Speech Processor ROM
By: lynchaj on Sun, 07 April 2024 18:13 |
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Re: Reverse-Engineering the Speech Processor ROM
By: lynchaj on Mon, 08 April 2024 03:46 |
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Re: Reverse-Engineering the Speech Processor ROM
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Re: Reverse-Engineering the Speech Processor ROM
By: lynchaj on Tue, 09 April 2024 04:22 |
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Re: Reverse-Engineering the Speech Processor ROM
By: lynchaj on Tue, 09 April 2024 09:49 |
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Re: Reverse-Engineering the Speech Processor ROM
By: lynchaj on Tue, 09 April 2024 10:50 |
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Re: Reverse-Engineering the Speech Processor ROM
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Re: Reverse-Engineering the Speech Processor ROM
By: lynchaj on Thu, 11 April 2024 09:56 |
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Re:TMS700x Memory Interface Mode Timing Spreadsheet UPDATE
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Re: What TMS7000 Family Data Manual Version Am I Using?
By: lynchaj on Fri, 12 April 2024 13:54 |
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Re: What TMS7000 Family Data Manual Version Am I Using?
By: lynchaj on Fri, 19 April 2024 03:37 |
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DAISY256 works
By: lynchaj on Mon, 22 April 2024 03:36 |
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Re: DAISY256 works
By: lynchaj on Mon, 22 April 2024 12:57 |
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Re: DAISY256 works
By: lynchaj on Mon, 22 April 2024 15:10 |
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Re: DAISY256 works
By: lynchaj on Tue, 23 April 2024 03:54 |
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Re: DAISY256 works
By: lynchaj on Tue, 23 April 2024 12:02 |
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Re: DAISY256 works
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Re: DAISY256 works
By: lynchaj on Sat, 27 April 2024 12:12 |
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Baud Rate Tables for 70x1, 70x2, 70Cx2
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Re: DAISY256 works
By: lynchaj on Mon, 29 April 2024 04:16 |
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Re: DAISY256 works
By: plasmo on Mon, 29 April 2024 05:52 |
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Re: DAISY256 works
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Re: DAISY256 works
By: plasmo on Mon, 29 April 2024 20:25 |
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Re: DAISY256 works
By: lynchaj on Tue, 30 April 2024 04:44 |
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Re: DAISY256 works
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Re: DAISY256 works
By: lynchaj on Tue, 07 May 2024 04:50 |
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Re: DAISY256 works
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Re: DAISY256 works
By: lynchaj on Wed, 15 May 2024 03:38 |
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Re: DAISY256 works
By: scruss on Wed, 24 July 2024 15:46 |
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Re: DAISY256 works
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Re: DAISY256 works
By: lynchaj on Sun, 16 June 2024 11:21 |
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Re: DAISY256 works
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