Hermes status

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Pr0f
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Re: Hermes status

Post by Pr0f »

I don't think it does matter Derek - but be careful as some of the NEC or NS parts are listed as 6MHz versions - not the 11MHz needed in the QL


RWAP
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Re: Hermes status

Post by RWAP »

Has anyone tried this one:

https://www.jotrin.com/product/parts/D8749H

1011 in stock at the moment according to that website. We could maybe place a bulk order.


Silvester
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Re: Hermes status

Post by Silvester »

Damn! I could potentially have picked up thousands of these back in the 1990's. BT used 8749 as controller on their 30-channel PCM cards. Just before I left I scavenged a dozen of the cards thrown in a skip. They also used Ferranti ULAs - never found any info on them though.

May be worth having a poll to see how many 8749's might be wanted?
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David
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Re: Hermes status

Post by Silvester »

RWAP wrote:Has anyone tried this one:

https://www.jotrin.com/product/parts/D8749H

1011 in stock at the moment according to that website. We could maybe place a bulk order.
Ha! In the last few minutes the page at jotrin is flagging it as a 'HOT' item (though still 1011 remain). :lol:


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Re: Hermes status

Post by RWAP »

The only issue is that we do not know whether these are 11Mhz chips...


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Ruptor
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Re: Hermes status

Post by Ruptor »

RWAP wrote:The only issue is that we do not know whether these are 11Mhz chips...
The datasheet is on the sales page so if that says 11 MHz it answers the question.
I wonder if the plastic ones are 8749 because I remember the window ceramic is expensive so to make OTP parts a manufacturer used the EPROM chip. To make a different technology on the chip also cost more in those early days so they made one chip and put it in different packages. People found different ways to erase the EPROM through the plastic like grinding some off and using a more powerful UV light because OTP was much cheaper. :)
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Silvester
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Re: Hermes status

Post by Silvester »

AFAIK only early 8748 were 6MHz (25v & 23v programming).

Intel D8748H/D8749H are HMOS 11MHz (21v & 18v programming).

Derek posted appropriate datasheet earlier : https://www.qlforum.co.uk/download/file.php?id=4597

PS. Also site page says: Up to 1.35 us Instruction Cycle (which is 11MHz /3 /5 )


David
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Re: Hermes status

Post by Nasta »

Silvester wrote:Damn! I could potentially have picked up thousands of these back in the 1990's. BT used 8749 as controller on their 30-channel PCM cards. Just before I left I scavenged a dozen of the cards thrown in a skip. They also used Ferranti ULAs - never found any info on them though.

May be worth having a poll to see how many 8749's might be wanted?
I have about 10 in my stock...
Regarding ULAs, these are customized anyway so you would not be able to find data except perhaps a 'high level' block diagram in some service manual for those cards.
I think NEC did OTP (one time programmable plastic case) 8749, and also a 44-pin PLCC version. The problem with either, as with any OTP part that has long been out of production is that they come from the surplus market and may have already been programmed for some purpose but never used, and hence became surplus.


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Pr0f
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Re: Hermes status

Post by Pr0f »

As far as I have seen - the Intel branded ones are all 11MHz, the 6MHz parts are from National Semiconductor - they offered both 6 and 11MHz offerings - these are branded NS

Also some NEC OTP ones I bought were 6MHz - but they were also already programmed, so basically just garbage.

It's curious he lists them as Motorola, but they are labelled up Intel and have Intel date codes on them...


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Re: Hermes status

Post by Derek_Stewart »

Hi,

I have managed to programme: Intel D8749H, NEC uPD8749HD and tested okay on a QL.

So it looks like the Hermes v2.2 rom code an the HiLo Systems ALL03A programmer can programme the Hermes chips.

I can provide this programming service, assuming the 8749 are available.

I also can provide the Hermes floppy disk and reprint of manual.


Regards,

Derek
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