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Need Tektronix TDS220 firmware file
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Beerden:

--- Quote from: Nprod on December 20, 2017, 11:31:28 am ---Reviving this post again - does anybody here have TDS220 firmware that's 2.0 and later? I also saw that you can upgrade a TDS2CM module to a TDS2MM one if you swap out the RAM and EPROM and then flash the TDS2MM.hex on it as described here: http://www.edaboard.com/thread8031.html

Sadly that thread is ancient and they only gave out the .hex file for it via PM... If anybody has these it would be greatly appreciated.

--- End quote ---

Thanks for reviving this post. Any word on the firmware 2.0 and later for the TDS220 (does it exist?)

Anyway, I have some additional info to add here:

A FLASH memory device can be used in place of the OTP EPROM for the TDS220 main board.

The EPROMs are getting harder to find (and they're one-time programmable!), but the FLASH "cousins" in these 32-pin PLCC packages are still available.

I was able to change the AM27C040-150JC OTP EPROM at socket U302 on the TDS220 main board to a AM29F040B-90JC (5V) FLASH (AMD/Spansion) already handy from my personal stash.

There is a small pin difference between the 27C040 32-pin PLCC and the AM29F040B-90JC 32-pin PLCC:

 pin 1 is Vpp on the 27C040 OTP EPROM, but is A18 (address bit) on the 29F040B
 pin 3 is A18 on the 27C040 OTP EPROM, but is WE# on the 29F040B

This pin difference needs to be corrected to work with the 29F040B; luckily the solution is already provided for by R306 and R307 resistor options for the U302 socket that connects pin 1 to pin 3:

Remove the 39.2 Ohm 1206 size resistor at R306
Install a 1206 size shunt (0 Ohm, or short length of wire) at the empty pads for R307
Insert the 29F040B in the U302 socket

My scope was at v1.16 and now it's v1.19!

I'm looking into the TDS2CM upgrade to TDS2MM now... :)
scopeman:
Bin file for the TDS2MM and instructions to update a TDS2CM to a TDS2MM is attached.

Sam
W3OHM
Beerden:

--- Quote from: OH2LIY on January 04, 2018, 05:31:19 pm ---Hello, I did try this with no luck. I replaced SRAM to Sony cxk581000am-70  (standard 128kx8 SRAM, first what I did find in my storage). I didn't have 27C040, instead I used 29F040. Using 29F040 CM (plain communication software) works nicely with bigger memory, but  when replaced to MM software, scope just freezes during boot up. 28C040 vs. 29F040 should be similar, if scope don't try to write anytyhing to memory.



OH2LIY

--- End quote ---

The difference between the 27C040 and the 29F040 is three pin assignments, Vpp and A18 at pin 1 respectively, and A18 and WE# at pin 31 respectively. So without a bit of PCB modification, the 29F040 is not expected to work as a drop-in replacement.

Pin 1 of the 29F040 is A18, the upper address bit, which on the 27C040 is at pin 31. Pin 31 on the 29F040 is the WE# pin. The TDS2MM firmware is likely larger than the CM firmware and may need access to this pin.

It is unlikely, as you guessed, that software would try writing to this region of memory, so it should be safe to connect pin 1 to pin 31 on the PCB. This same "trick" is done on the TDS220 motherboard, but is actually provided by a resistor shunt option, and a 29F040B works there!

To support this connection, the AM29F040 datasheet says (paraphrased), "Write cycles are inhibited by holding any one of OE# = low, CE# = high or WE# = high. To initiate a write cycle CE# and WE# must be low while OE# is high", so in the case where A18 is attached to WE#, then OE# = low (read cycle) will override the WE# function for any state of A18.

I also hope to use a 29F040B on my TDS2CM, but the TDS2CM will require a wiring modification. Unfortunately, pin 1 of the U206 PLCC socket is directly connected to a via to the ground plane (Vpp programming voltage on the 27C040), so this makes modification for a 29F040B tricky for pin 1, but not impossible.

As far as I can tell A18 traces from pin 1 of the J101 header to the 20-pin PLD at U104 pin 4 U104 and to pin 31 of the U206 PLCC socket (A18 on 27C040), so access to A18 to pin 1 of the 29F040 might be easiest as a wire from pin 4 of U104.

Also, for the 32-pin SRAM option, A18 is left floating on the PCB, so perhaps attaching a wire to ground at U204 pin 1 (A18) would allow larger capacity SRAM chips to work properly (often easier to source these days!); a floating address pin could lead to unexpected behavior.
OH2LIY:
Tnx Beerden! I did compare datasheets between 27C040 and 29F040, but probably I was too hurry/lazy and didn't spot that small difference (I did have nagging feeling, that there was something HW differences between proms and flash).


Ramppa
OH2LIY:
Success! Bend flash pins 1 and 31 up (can be done once). Then use narrow tape strips between flash and socket pins  (I used capton, it worked nicely), and just solder flash pin 1 to  U104 pin 4 and flash pin 31 to closest VCC (pin 32 is closest, just bridge them).


Ramppa
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