Bump: Does anyone know anything about the pinout of the lcd driver? I suspect is is connected to the data bus, address bus and control lines of the z80, so I could tap into the I/O of the cpu there.

Does anyone know anything about this module: pinouts, datasheets?


Edit:This is what I found so far: it's a Toshiba T6K04


Here are 17 pins going from the main board to a little pcb with the driver attached. For a z80 interface you only need 12 pins and 2 for power. Still no idea what the pinout is of this 17 pin connection.

Is this correct? http://ripitapart.wordpress.com/2013/03/02/making-use-of-an-old-ti-83-plus-lcd-screen/
He describes the pinout of the module here.

But I WANT to do a ridiculous amount of soldering to my 83+ You know I already interfaced many devices with the linkport. I wanna take interfacing hardware to another level.

Is that I/O directly interfaced with the cpu?

The TI-83+ pictured above has a discrete Z80, so yes, you can tap directly into the Z80 bus. In fact, somebody else did that in the early 2000s, though I don't recall the Website it's documented on.

The TI-84+/C/SE does indeed have a keyboard matrix. It should have an 8+7+1 layout: 8 rows, 7 columns, and the ON key. However, the keyboard pins are protected by transistors, making them unsuitable for GPIO. There is indeed an external data bus and address bus. The address bus on the TI-83+SE was 24 bits: 23 address bits, plus a bit selecting RAM or flash. I don't know if the TI-84+/C/SE ASICs still have that RAM/flash select bit, but they all probably nevertheless assert the address onto the bus for RAM read/write. The LCD driver almost certainly shares the same data pins. Mysterious sources indicate that the TI-84+/C/SE TA3 ASIC also feature four external chip select pins for future expansion. The Z80 can address them by reading/writing ports 3C-3F. As far as I know, they are unused. On the TI-84+CSE, they read non-zero, but the value never changes, so it may be garbage. Unfortunately, nobody has pinout information. However, some high-resolution photographs I took of my revision A TI-84+SE and my shiny new TI-84+CSE may be useful to you. As far as I can tell, the right side has keyboard matrix pins, the top has USB stuff, the left has the data/address bus pins, and the bottom may contain more, plus miscellaneous stuff like the CPU clock frequency and the 32768 Hz crystal.

Next weekend I'll borrow the oscope from work and take apart 84+SE (yet again) to see if I can find anything useful, I'm really curious about the $3c-$3f ports DrDnar mentioned. This is my last 84+SE so I'm not going to try anything crazy, just write ports and test pins. My last 84+SE project was a complete failure. Tried to make a backlight but I think I cracked the LCD somewhere trying to remove the glued backing. The contrast was so dim, I could barely make out what was on the screen. On this current one, I soldered wires straight to the link port so I wouldn't have to plug and unplug my bootleg (but useful) breakout cable.

Got it. I would love to have my own scope that I could use whenever I wanted, I was ordering a DSO nano today.