Pi Pico[W] Peripheral Expansion Box Side Port Device

[+chue]

Thanks @RickyDean I appreciate the help. Hopefully Jason will have some things for me to try.

[RickyDean]

1 minute ago, chue said:

Thanks @RickyDean I appreciate the help. Hopefully Jason will have some things for me to try.

You may try another sd Card also, could be finicky like the FG99?

[JasonACT]

1 hour ago, chue said:

Hopefully Jason will have some things for me to try.

If "CALL TIPI" in TI BASIC isn't working, then for some reason the TI isn't seeing the DSR ROM, which is apparently being loaded, verified by your tests of removing the files and getting 4 or 5 LED blinks.  Without the DSR working properly, the memory expansion will be switched off (also the cartridge GROM/ROM space too) because it only gets switched on after the DSR has verified you don't have other hardware installed.  Does the speech synth work?  That's fully contained in the Pico's flash memory and will tell if the 74LVC245's are operating properly...  You can also try Mini Memory and switch the DSR on and dump the first few bytes at >4000 to check the ROM?

 

Also, your Pi Pico W doesn't appear to be genuine, it has an ESP WiFi chip from the look of it (not a cyw43) and it might be locking up the Pico after the DSR has been loaded from the SD card (WiFi is the last thing to be configured).  I can build a firmware version without WiFi enabled to check this.

 

What's in your autoload.cfg file?

PPEB2.ino.uf2.zip

Edited February 3 by JasonACT
Added no-WiFi firmware

[JasonACT]

I'm extremely reluctant to post this, I have not had circuit boards made from these files, so the files are completely "unverified".  But here are the DipTrace and generated Gerber files with R4 moved and re-purposed from a 10K ohm pull-up to the 470 ohm current-limiter for the SD clock.  I really hope the files have no issues.

Speech.zip

[+chue]

3 hours ago, JasonACT said:

Does the speech synth work?

Not really, but it does something... This is with the "no wifi" firmware.  Sorry about the shaky video and the 4 year old talking in the background:

 

 

If you have trouble seeing the video, I type in CALL SAY("ONE") and the audio out is "UH-OH, UH-OH, UH-OH".

 

"CALL TIPI" still doesn't work with the no-wifi firmware.

 

3 hours ago, JasonACT said:

your Pi Pico W doesn't appear to be genuine

That's what I get for going cheap.  Worst case scenario we chalk it up to bad hardware, and I'll have to buy some real PIs.

 

3 hours ago, JasonACT said:

You can also try Mini Memory and switch the DSR on and dump the first few bytes at >4000 to check the ROM?

Not really sure what to do here but will give it a go and see.

 

3 hours ago, JasonACT said:

What's in your autoload.cfg file?

CRU=1
PCODE=0
BAUD=115200

WFCC=AU
WIFI=[MY WIFI]
PASS=[MY PASSWORD]
SNTP=192.168.1.1
TZHR=10
TZMN=0
TMFT=1

;D1MAP=/BLNK.DSK,RO
;D2MAP=/BLNK.DSK,RO
;D3MAP=/BLNK.DSK,RO

;CART=/carts/marioG8.bin

 

 

Thanks for the help!

[RickyDean]

8 minutes ago, chue said:

That's what I get for going cheap.  Worst case scenario we chalk it up to bad hardware, and I'll have to buy some real PIs.

I got my Pi's from Amazon, here's the link.

https://www.amazon.com/dp/B0BMP5546H?psc=1&ref=ppx_yo2ov_dt_b_product_details

 

But.....these have headers already installed, so you would have to remove those.

Edited February 4 by RickyDean
spelling

[JasonACT]

9 minutes ago, chue said:

If you have trouble seeing the video, I type in CALL SAY("ONE") and the audio out is "UH-OH, UH-OH, UH-OH".

That's interesting!  Both Pico CPUs are working, as they work together to produce the speech sound, but the TI isn't able to read the vocab data from the speech ROMs for some reason - it can't find the word "ONE" in there.  You might have a bad 74LVC245 or a solder issue - check under the board - maybe post a picture here too?

[RickyDean]

1 minute ago, JasonACT said:

 maybe post a picture here too?

Jason he did post a picture on page 6 here a few post back. But you may want him to post some more close ups?

[JasonACT]

4 minutes ago, RickyDean said:

Jason he did post a picture on page 6 here a few post back. But you may want him to post some more close ups?

Yeah, it's a good picture, but it's worth getting one of the underside too.

[JasonACT]

Mini Memory - Easy Bug: ("C1100" <enter> "1" <enter> "." "M4000" <enter><space><space><space><space><space>)

 

Edited February 4 by JasonACT

[+chue]

19 minutes ago, JasonACT said:

maybe post a picture here too?

 

[JasonACT]

12 minutes ago, chue said:

 

That all looks good to me.  Maybe try re-seating the '245 chips?

[+chue]

29 minutes ago, JasonACT said:

You might have a bad 74LVC245 or a solder issue

I’ll check for continuity between the chip pins and the underside. If everything is good I’ll swap in some other 245s that I have.  This may be tomorrow though 

[+chue]

1 hour ago, JasonACT said:

Mini Memory - Easy Bug: ("C1100" <enter> "1" <enter> "." "M4000" <enter><space><space><space><space><space>)

These are the values that I get.  Note that I haven't reseated the 245s yet.

 

[JasonACT]

14 minutes ago, chue said:

These are the values that I get.  Note that I haven't reseated the 245s yet.

Looks like you have 1 bad output bit >02 which is always low.  That's possibly on the data in/out '245 chip U3 because the address chips (U4 & U5) are picking up the correct addresses.

[JasonACT]

This trace (in blue) going to the TI, or the other one coming from the Pico:

 

 

[+chue]

2 hours ago, chue said:

I’ll check for continuity between the chip pins and the underside.

Continuity between the pins and the underside of the board is good.  I remembered I have a generic logic chip tester and used it to test the top chips (U3, U4, U5, U6).  It will display the chip name if it IDs it.  It displayed the correct chip names for all four chips.  After reinstalling the chips I went into EasyBug and examined the bytes at 4000.  Same result as before - bit >02 always low.

 

50 minutes ago, JasonACT said:

This trace (in blue) going to the TI, or the other one coming from the Pico

I checked for continuity for the traces in blue.  Both sets of traces show continuity at the various points.  Set 1 showed continuity from the female side of the card connector to the PCB edge to U3 to the other side of the PCB edge.  Set 2 showed continuity from the PICO to U5 to U4 to U3.

 

The only thing I can think of is a short to ground on one of the above set of traces.  I'll see if there is one.

 

Edit: There is no short to ground.

[JasonACT]

41 minutes ago, chue said:

Edit: There is no short to ground.

The attachment below is a bench-tester (do not plug this into the TI) which sets U3 to enabled-output mode and toggles all 8 data bits once a second (it also flashes the LED at the same time).  You can run this without U3 inserted to check your Pico is working, using a DMM on pins 1, 2, 4, 5, 6, 7, 9 & 10 to see if it's outputting the right signals.  Then plug in U3 to check it's still getting the 8 data signals (U3 pins 2-9) and is transferring them to the other side of the chip (U3 pins 11-18).

pintest.ino.uf2.zip

[JasonACT]

Another bench-tester, this one alternates between >AA and >55 every second.  Unlike the last tester, this one should show up issues where a short to a neighbouring pin is an issue.

pintest2.ino.uf2.zip

[+chue]

10 hours ago, JasonACT said:

The attachment below is a bench-tester (do not plug this into the TI) which sets U3 to enabled-output mode and toggles all 8 data bits once a second

I tested at the suggested locations from the PI to U3 to the edge of the PCB, with and without U3.  Signals are propagating as they should.  I have yet to test the TI side of J1, the edge connector, but will do so.  The multimeter alternates between 0 and 3.3 volts.

[+chue]

5 hours ago, JasonACT said:

Another bench-tester

I will take a look and report back.  Thank you!

[+chue]

Using the pintest2 firmware, I was able to confirm that the data signals (D0-D7 in link below) are good.  I used two Pico PEB PCBs connected together to confirm that the signals are coming out of the edge connector (J1):

 

 

I used the sideport pinouts from here as a guide: https://www.unige.ch/medecine/nouspikel/ti99/pinouts.htm#Side

 

At this point, I'm thinking I should just build another Pico PEB, but with a genuine PI.

 

Edit: Just to be more descriptive - I am seeing at pins D0-D7 on the edge connector, the voltage oscillating between 0 and 3.3.

[RickyDean]

22 minutes ago, chue said:

Using the pintest2 firmware, I was able to confirm that the data signals (D0-D7 in link below) are good.  I used two Pico PEB PCBs connected together to confirm that the signals are coming out of the edge connector (J1):

 

 

I used the sideport pinouts from here as a guide: https://www.unige.ch/medecine/nouspikel/ti99/pinouts.htm#Side

 

At this point, I'm thinking I should just build another Pico PEB, but with a genuine PI.

 

Edit: Just to be more descriptive - I am seeing at pins D0-D7 on the edge connector, the voltage oscillating between 0 and 3.3.

Do you have a reflow blower? You can detach your Pico and use an original there instead.

[+chue]

6 minutes ago, RickyDean said:

Do you have a reflow blower? You can detach your Pico and use an original there instead.

I do and I might give it a try.  I do have concerns about overheating the PI itself as well as surrounding components.  I do have some low temp solder (chip quik) I can try as well.

[RickyDean]

I use a 5/16"(8mm) nozzle and lay flux around the unit then after getting the blower up to temp, I place a pointed object or a very small screwdriver at a leverage point under the board, then go around the unit back and forth and around the edges till the unit starts releasing. Then I get a small pair of pliers, needle nose and gently pick up while continuing the process till the unit is free. don't spend a lot of time in one place and only use as much heat as needed to get the job done. Then use solder wick and a hot iron to get the remaining solder off the board.