On Wed, 28 Mar 2007 08:29:49 +1000, Franc Zabkar
wrote:
On Tue, 27 Mar 2007 23:28:43 +0200, Joachim Wunder
put finger to keyboard and composed:
Thanks, Franc, for your kind offer. I guess I have just found a good
source in Germany for 74S188 from National. Hmmm, I am still curious
of which programmer you actually have.
I have an old Sunshine Expro-60.
Ah, ok. Donīt know this device, but must be powerful.
And, can any programmer even
copy an existing 74ALS188 if it (the programmer) can program an unused
74ALS188? Please pardon my stupidity, but except programming EPROMs
and 8748 I never did any 'acrobatics' with PROMs...
Joachim
AFAIK these PROMS have no security bits so you should be able to read
their contents without any trouble. The 74S188 uses fusible link
Yes, the same applied to my two 8748 (one on the old PCB and one on
the new PCB): No security bits, so I was able to read them out,
finally.
Thanks God. The source codes (they slightly differ from
each other) both show a couple of the following opcodes:
movx a,@r1
movx @r1,a
movx a,@r0
movx @r0,a
That first confused me a little, īcause these movx commands normally
reference external memory, but \RD and \WR pins of my 8748 are not
connected to anything on the PCB. Hmmmm, strange, isnīt it? The
74ALS188 is connected to port P0 (i.e. the BUS) of the 8748. So, the
outl bus,a
ins a,bus
commands seem obvious to me. Hmmm. Well, anyway, I am very satisfied
that the 8748īs EPROM content was readable at all.
technology which means it would require a different programming
algorithm than an EPROM, but accessing its data should be no
different.
OK. Sounds fine. Meanwhile I even googleīd enough to know now more
about the programming algorithms for PROMs in general.
BTW, what good is a device programmer that is unable to verify (ie
read and compare) the device it has just programmed? ;-)
Thatīs absolutely right. ACK.
Kind regards,
Joachim