Turbografx/29F016 Question

I'm trying to use a 29F016 flash chip with my Turbografx, and haven't been able to get it to work. It's brought up a few questions at the same time that I was wondering if someone could shed some light on. Basically, I've added a 40pin ZIF socket to the back of my turbo that allows me to play games via EPROMs up to 8Mbit. I have a bunch of 29F016 roms kicking around from SNES repro's, and was wondering if it was possible to use them with the turbo rather than having to UV erase eproms? I use the same adapter boards as outlined here: http://www.mmmonkey.co.uk/programming-29f032-eeprom-on-gq-4x/
I tried to use these along with the programmer adapter in the turbo (so basically standard pinout ZIF in my turbo -> TSOP-Willem programmer adapter -> 29F016 on Adapter III board), however the game wouldn't boot, just a white or black screen. I tried tying A20 high and low to just use the first 8Mbit for my game, but neither worked. How should I go about using these on my Turbo?

Also, the HuCard pinouts I've been looking at state that pin 24 is /CE, but also A20:
http://www.hardwarebook.info/HuCard
http://nintendoallstars.w.interia.pl/romlab/pceconn.htm
So is it possible to use a 16Mbit flash chip with the turbo? If so, how would you wire it up?

Sorry, this is a bit loaded and probably really confusing the way I have described it. It's also ridiculous because I should just use a 27C080 EPROM, I know. I just happen to have a lot of free time and want to figure this out. Here is a picture of my turbo with the setup I'm attempting to use to play a game via the SNES Adapter board with a 29F016 on it.

That adapter seems to be just for programming. I would think you would have things left floating if the Turbob socket is wired for 32 Jedec.
Check the states of RESET, WE and BUSY.

Wouldn't it still work since these are designed to be used in SNES carts? None of those pins are wired up when used to replace nintendo mask roms as far as I can tell

I rechecked everything like you suggested and found that /CE was tied to ground for programming. I cut that trace and now the games start up, however I get some graphical glitches and the games crash frequently. I currently have A20 grounded to only use the first 8Mbits, is that correct? Is there something I'm missing that would be causing the games to have glitches?

The adapter III uses SNES rom pinout which is slightly different than Jedec. You may have a few mixed address lines.

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Yeah, I'm using a TSOP-Willem programmer adaptor with a zif socket on it as a bridge between my turbo (which is jedec) and the adapter III so that it conforms it back to the jedec standard. I think that something else is different somewhere on the programmer board other than grounding /CE that's causing problems. Either that or I've messed up trying to bankswitch only the first 8Mbits of the 29F016. I routed A19 back to the proper pin (pin 1 for jedec). The /CE signal (pin 22) was also routed up to pin 36 on the TSOP adapter, so I cut that trace as well, but it had no effect.

Got it, had to tie /WE to +5v for it to work. Thanks for the help busted, appreciate it!

Hi there mikey. I'm trying for what you have done as well but am going off the extension port on the back. It looks like it has all the needed pins to the HuCard connector, but so far all I get is a white screen. When you wired up yours did you treat pin 24 on the HuCard connector as CE or A20? Also when yours was finished did you have 32 pins on your ziff wired up with the extra Hu_Detect tied to ground?

darknezz19 said:

Hi there mikey. I'm trying for what you have done as well but am going off the extension port on the back. It looks like it has all the needed pins to the HuCard connector, but so far all I get is a white screen. When you wired up yours did you treat pin 24 on the HuCard connector as CE or A20? Also when yours was finished did you have 32 pins on your ziff wired up with the extra Hu_Detect tied to ground?

Click to expand...

I don't think it matters for the card detect pin (hucard pin 1). I seem to recall connecting it to ground and leaving it floating, both worked. I believe it's more there for the CD add on and system cards. As for pin 24, connect it to /CE. For the rest, just connect all the pins of the eprom to the corresponding pin on the turbo's expansion connector and it should work. I'm actually about to do the same thing and move the ZIF to an external board as well

My issue is I'm using the PC Engine extension port pinout that's on the web and it's different from the TG16 port. The D0-D7 address are swapped but that looks like that's all. Here's the pinout for the PC Engine, the TG16 service manual is on there as well and it shows the difference.

http://www.gamesx.com/misctech/pcebp.php

Well from what the diagram says you could connect A20 of the expansion port to the eproms /CE, as that's what it's often used for and is labelled as a system function. That, or you could just tie the eproms /CE and /OE pins to ground to enable them. +5v turns them off, and GND activates those functions, so if you just tie them to ground then the chip will always be enabled and it's output will always be enabled. If no eprom is in there, it won't matter because it won't connect to anything and the hucard slot should work normally.