Pirelli DP-L10 display subsystem (was Re: JTAG setup for Pirelli DP-L10)

Steve Markgraf steve at steve-m.de
Sun Jul 28 08:53:13 UTC 2013


Hi,

On 28.07.2013 09:20, ubuntugirl wrote:
> Were you ever able to figure out just how the backlight works on this
> display? Your code has a comment about a particular register in the
> SPCA supposedly turning the BL on or off, but looking at the pin
> interfaces of this SPCA in the Nokia schematic, I don't see anything
> even remotely related to the backlight... Yet the original firmware is
> able to not only turn this BL on and off at will, but also change the
> brightness - during calls, the display dims instead of blanking
> completely.

Yes, and it took me a while. The basic 'on/off' is controlled by the
SPCA with the code we have, the brightness is controlled by the
PWL-unit of the Calypso, but inverted if I remember correctly.
Just play with the bl_level() function a bit.

> On a related note, were you ever able to figure out the pinout of the
> 30-pin flex between the main PCB and the LCM? If this pinout were
> known, I could probably trace out the stuff of interest to me (like
> the backlight) on the main PCB using your layer pictures, but if I
> have to reverse-eng the LCM itself, that might be a bit above my skill
> level. :(

At one point I soldered wires to all connections and hooked them up to
a logic analyzer. It's a 16-bit interface and it was quite easy to
figure out what was what. For all the initialization only 8 bits are
used, for the actual display content you switch to the 16-bit mode.

> Bummer. But just out of curiosity, how did you figure out that it's an
> 8051? Did you see the original phone fw pushing something to the SPCA
> that looked like 8051 instructions?
> FWIW, the 554 datasheet describes its CPU as a "32-bit RISC processor"
> - too closed to even name what it is!

Now that I see the "32-bit RISC processor"-comment as well... no idea
where I got that from, it's most likely wrong then. I didn't look at
the instructions, but as far as I remember I've seen a code blob
being uploaded.

Regards,
Steve





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