D2716 eprom

[Guest]

Hi
i know this is a really really old type of eprom but i seem to be having a few problems with the s4 on them, I have tried the s4 8 bit eprom v3.00 and s4 16 bit eprom v1.22 lib's with no luck

i believe the D2716 is a nec eprom but the s4 refuses to say its blank even when a old bbc b pc and watfords electronics eprom programmer says it is and this is just on one standard 2716 setting that it has!

so i know the eprom is blank, but the s4 using the test button to see if its blank it says every location has data in it, when trying to program it still wont program it saying every location has different data on the verify process

The old bbc b works fine and programs the eprom well and a checksum.......
now here is the funny bit , if i then put the eprom back into the s4 and do a checksum it matches the bbc b checksum! but if i examine the data on the s4 it reads totally different to what is actually in the eprom

i have tried several different read processes on the 2716 using different manafactures and still no joy

i am just puzzled on why i cannot get the s4 to make sense of these old eproms to program when a extreamly old bbc b with eprom programmer works fine with no problems

i know these are old eproms but the reason for needing to program such old eproms is they are direct replacements for duff ones i have in a old 1978 space invaders machine and it would be nice for the s4 to do them rather than having to set up the old faithfull bbc B and equipment

many thanks
Andrew

[Dataman (Neil Parker)]

Hi Andrew,

The S4 should program any 2716 device the DS2716 as far as I can tell could be Intel or NEC, both of which are directly supported in library 3.00 for 8bit EPROMs.

If you continue to have problems with this device then please send the programmer and a couple of samples devices to us for testing.

Regards,

Neil Parker
Tech Support

[Guest]

Hi Neil

Thanks for your reply, i have done a little more research and this is what i have found
all other types of eprom program/verify fine on the S4 (2732, 2764, 27256 and biger types)

If i program a 2732 and set the S4 device to be 2716 it reads fine and correctly as a 2716 no problem, so i am sure the S4 is not faulty in its operation

If i do a checksum on both the D2716 and the first half of the 2732 it is identical (1E513). so the checksum feature is reading fine


but if i put these D2716 devices in the S4 and do a compare with memory this is what i get

00001 RAM=C3 ROM=C0
00002 RAM=C9 ROM=C0
00003 RAM=16 ROM=00
00004 RAM=21 ROM=20
00005 RAM=84 ROM=80
00007 RAM=7E ROM=30
00008 RAM=A7 ROM=A0

Can you see the pattern?
It seems the S4 is reading the first character correctly, but not the second on most times

I am wondering if the 2716 devices i have are very old and very slow and therefore too slow for the s4 to read correctly so its reading them too fast and therefore wrongly on the lower data lines.

Perhaps the S4 reads the data lines in sequential order starting at D0 (lsb) upwards and when it starts to read the data it has not yet stablised from the D2716 eprom but when it gets to the higher data lines (msb) they have stablised enough for the data to be mostly correct


The D2716 devices i have, have no speed on them like the later ones that read like D2716-35 so i believe they could be very slow devices

My S4 i believe is a early serial number if this helps (17XXX) but it does work well!

1) Is there any way of slowing down the S4 so i can prove this is might be whats hapening?
2) Does the S4 do anything different between comparing and checksum in its timings of reading the eeprom?

many thanks
Andrew

[Dataman (Neil Parker)]

Andrew,

Can you try to load and compare the 2716 at the address 800H instead of 0H. I remember that this was recommended for the S4 due to a quirk with the hardware.

Let me know how you get on.

Neil

[Guest]

Hi Neil

I tried that and it works a treat! its reading the eproms fine now using 800H as its start address in the S4 memory.

Is there any way i can make a library for the S4 so it starts and uses 800H as its start address automatically instead of having to remember to type it in every time for the 2716 eproms?
Just a library rom with the standard 2716 settings starting at 800H in the S4 memory perhaps?

many thanks
Andrew

[Dataman (Neil Parker)]

Andrew,

Yes, you can set the 2716 device using the PROM key, you can then hit BURN and set the range to 00800-00FFF=00000 then hit ESC. If you now hit FUNC > LIB, this will copy the active library including any settings, from the program area into the user RAM where it will place it between 08000-0FFFF.

If you now find a blank 27C256 and BURN it as follows: 08000-0FFFF=00000. The address structure being the start and end address in S4 RAM and then the destination address in the chip.

If this new library chip is loaded, LIB > ENTER, then you will find that the 2716 device is selected by default and if you hit BURN you will see the address range will also default to 00800-00FFF-00000. As requested.

Regards,

Neil

[Guest]

Hi Neil

That is great! thankyou so much for your help, you are a mine of information!

I do have 1 more question related to the S4, i remember a while back being able to download from the site pinouts showing what pins to connect serial eeproms to on the S4, devices like the 24xx and 93xx series, but i cannot seem to find this info now. i remember it was not listed in the adaptor.txt file but as a seporate file but i cannot remember what it was called then and since last programing these serial eeproms i now no longer can find the info in files on the pc

can you help again?

thanks again
Andrew

[Dataman (Neil Parker)]

Andrew,

The document can be found on our website here:

http://www.dataman.com/dataman-s4-serial-adapter

Regards,

Neil

[Guest]

oh thats great!
thanks again Neil

regards
Andrew