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Stuart

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Stuart last won the day on September 18 2016

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About Stuart

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    Southampton, UK

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  1. Nothing new ... but have been having an e-mail chat with a chap helping to restore a Royal Observer Corp Group HQ Bunker in Scotland (that's the northern bit of the UK!). This is one of a number of HQ Bunkers that would receive information from smaller 3-man underground bunkers about the spread of nuclear fallout in the UK in the event of someone dropping one or more nuclear bombs on us. Operational up to the early 90's. They've got a number of bits of kit that use the TMS9900 and 9995 that they're restoring, and they were after one of my TMS9900 PCBs to use as a simple way to test their processors and clock chips. https://www.facebook.com/28Group/ if you're interested. It's a Facebook page but if you haven't got an Facebook account just click the "Not Now" link towards the bottom right of the login banner displayed and you can scroll through to your heart's content and try to spot our favourite processors.
  2. It is being sold by Jaime, who designed the NanoPEB.
  3. http://www.stuartconner.me.uk/ti/ti.htm#connecting_serial_mouse
  4. Indeed, which means that you'd have to sit at your terminal typing away at a steady speed, never slowing down or deviating, never stopping ... I suspect what dhe vaguely remembers is that you could pop a 9903 in a 9902 socket (it is one pin shorter so has to go at one end of the socket), but the synchronous protocol and serial connections are different to the RS-232 interface provided by the 9902. You *can* design the board to support both but it needs a 25-pin serial connector and you need a terminal that supports the same synchronous connection.
  5. It's the LMF instruction - Load Memory Map File - opcode 0320 - from the 990/10 and 990/12 processors. They have 21 instruction formats - ouch!
  6. Did you look at [http://www.stuartconner.me.uk/ti/ti.htm#tipi_network_socket_interface], scroll down to: **************************************************** *Find CRU address of TIPI device. **************************************************** That code will find the CRU address of the TIPI. (Code is largely based on code I found elsewhere)
  7. Hi Fabrice, They're all yours. PM me your mailing address and I'll get them in the post to you during the week. If I then let you know the postage cost, can you PayPal me the money? Stuart
  8. I've been given the following: -- Approx 5 HM628128ALP-7 128KB static RAMs -- Approx 10 HM62256BLP-7 32KB static RAMs -- Approx 10 HY6264LP-10 8KB static RAMs Any use to anyone? They're free except for the cost of postage and packing from me in the UK. To post to the US will cost about UK£10. They're quite possibly from China. I haven't tested any of them. No guarantees or refunds! Stuart
  9. Have you looked at something like https://electronics.stackexchange.com/questions/286052/divide-clock-frequency-by-3-with-50-duty-cycle-by-using-a-karnaugh-map ? Pretty simple if you're not worried about the duty cycle.
  10. If you pull one of the 9901 programmable inputs either high or low then use the TB instruction to read the state of that input, then you'll know whether CRUIN will be high or low? So if you pull CRUIN high through a resistor and use it to measure a low input, it should be fairly obvious when it goes hi-Z?
  11. I use a USB-to-barrel connector power cable, and power the board from a USB socket on the computer I use for the serial terminal. I was given a 99110, but have only ever seen 99105s for sale on eBay. So at least one 99110 exists.
  12. If you're able, try replacing U10 and U11 on the card - both 74LS373. They provide the interface between the PIO connector and the rest of the card.
  13. If your power supply is OK (the voltage on each output pin should be marked on the PCB right next to the connector) then you might be better off by first replacing the two static RAM chips - those are the two larger chips marked "MCM6810P". You can get those off eBay. The VRAM RAM chips (the block of eight marked MCM4116... and TMS4116...) can and frequently do go bad, but they usually result in a corrupted display rather stopping the machine booting altogether. Get some decent quality cutters so you can cut the IC pins individually with the IC still on the board then you can remove the IC body, then you can unsolder and remove each pin individually. This will reduce the risk of damaging the PCB. Fit a turned-pin socket to the PCB to plug the new IC into.
  14. The PEB cable 'foot' that plugs into the console? (With some questionable soldering quality bottom right ...)
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