Palm Pilot LCD screen pinout in progress

[pproc]

OK, after some experimentation I am reasonably sure of the following on my palm pda type lcd (Picvue PC1721WE).
I'm not sure if it is for a genuine Palm PDA as the icons on the 4 corners of the "graffiti" interface pad are different from the original Palm PDA panel.

1. Its a 4bit monochrome panel
2. Has onboard EL driver using HV826 driver chip
3. Has onboard contrast voltage generation circuit

Pinout

20 D3
19 D2
18 D1
17 D0
16
15 CONTRAST (pwm ? 0 =>15V, 3.3V => 21.5V)
14 DISP_EN
13 GND
12
11
10
9 HSYNC (LP)
8 DCLK (CP)
7 GND
6
5 BKLIGHT_EN
4
3 touchscreen
2 touchscreen
1 touchscreen
0 touchscreen

I'm not sure of the VCC pin on this pinout because it doesn't seem to be directly connected to other chips on the
board or to the display lines. So I am powering
the panel by connecting 3.3V to the HV826 driver VCC pin.

I'm pretty sure of the DISP_EN, HSYNC, DCLK and D0 .. D3 lines, because I can bring up the screen for one frame with contrasty lines, placed where I would expect them e.g. Writing 0x8 every data clock to D3..D0 makes the 1st,5th,9th pixels on a line black. Writing 0x1 makes the 4th,8th,12th pixels black..

For these experiments I have been using Daltore's experimental data, driving the pixels with an approximate pixel clock period of 75uS.

However, the screen fades immediately after the first frame draw. So I have not yet been able to determine the VSYNC (FLM) pin (and perhaps a BIAS signal, though I don't see it on the PC0919WE07 schematic) and timing.

Again, any pointers to useful info would be appreciated - i am close, but not yet there !! Am wary of doing damage as I only have a couple of these screens and could really make use of them.