1702A programming (was Bugbooks - Mark 80 )

From: Dwight Elvey <elvey_at_hal.com>
Date: Wed Jan 27 17:54:30 1999

Programming the 1702A's
 Well in some sence I have a little egg on my face.
The programmer I have was infact designed for
1702A's but doesn't do it following
the specifications.
 First 1702 versus 1702A's. As was mentioned, the
1702's couldn't take the same duty cycle by 10X.
It isn't true that you can take a 1702 programmer
and program 1702A but you can take a 1702A programmer
and slow down the pulse rate and program 1702's.
The difference is that the 1702A's require an address
complement phase at the start of the cycle. This phase
doesn't effect the 1702's so the only issue is repeat
rate.
 Now to the issue with my MP7-03 board. The first PROM
I tried was either originally blown or I blew it out.
The programming voltage was about 53 volts. I cranked
it down to 47 volts and tried another PROM and it now
works fine.
 There is still the part I don't understand. The specifications
for programming the 1702A show a setup time for the
complement address at the start of 25 microseconds. The
MP7-03 is violating this by quite a bit. The Vgg
and Vdd are never pulsed to Vcc. The sequence is:
step0: time before zero
   Vcc 5V
   Prog 5V
   Vgg -9v
   Vbb 5V
   Vdd -9v
   address lines true and 0/TTL levels
   Data lines true and 0/TTL levels
step1: time 0
   Vdd to Vcc-47volts
   Prog to Vcc
   Vgg to Vcc-35volts
   Vbb to Vcc+12volts
   Address lines to Vcc and Vdd levels but complemented
   Data lines true and Vdd/Vcc levels
step2: time 50 microseconds
   Adrress lines to true, Vdd/Vcc levels
step3: time 150 microseconds
   Prog to Vdd
step4: time 2.5 milliseconds
   Prog to Vcc
step5: time 2.9 milliseconds
   Levels to the same as Step0

Repeat every 15 milliseconds for 30 cycles.

 If you'll plot this out, you'll see that there is zero
complement address setup time but the transition from
14 volts Vcc-Vdd to 47 volts Vcc-Vdd may compensate for
this. Without understanding the internals, I couldn't say
but it is not like the specifications.
 Part of the reason I'm posting the sequence used for this
tester is that it is a little simpler than following the exact
specification and may help some home made programmer. I
also ran some AMD 1702A's through it without problems.
 The good news is that I was able to program three backup
PROMs for my SIM4-01 board and I ran them to verify that
they where correct.
 Thanks for the help from Jonathan Levine who sent me a copy
of the document that made me realize that the firmware and
hardware should program 1702A's even if the specs didn't match.
Dwight
Received on Wed Jan 27 1999 - 17:54:30 GMT