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Subject: Sansa View - weekly update

Sansa View - weekly update

From: Robert Keevil <rkeevil_at_gmail.com>
Date: Sun, 12 Jul 2009 22:11:42 -0500

Hi,

I've been having a rather frustrating time recently banging my head
against the wall that is the Views LCD.

The Views OF LCD init routines seem to match the Ilitek ILI9320
controller, or possibly the Renesas R61505 - the registers for these two
devices are very, very similar. It is possible that the actual
controller is still something different again - I've been unable to
track down the datasheet for the ILI9321 (a GRAM-less version of the
9320?) or other Renesas controllers in the 61500 family.

The ILI9320 datasheet has allowed me to fill in a few gaps I had when
reading the disassembly of the controller init routines. These routines
in the OF appear to be sent to the LCD via an SPI interface - at first I
thought that all LCD transfers would be via this method until amiconn
pointed out that this would limit the screen to a maximum of 7fps, so
obviously another method is used. Despite advice from kugel and others
in IRC I've been unable to transfer data to the LCD via SPI, and I've
not been able to locate the actual routines in the OF which transfer
data to the screen. I am going to again trace the strings that are
displayed in the OF, hoping that now I am a little more familiar with
disassembly that I'll be able to track these down. Otherwise I'd be
happy to hear any other tips for working out how this device talks to
its LCD. Perhaps it is like the Gigabeat F - using SPI for command
transfer, and another method for data?

One other recent finding is that several registers and constants in the
Views OF seem to match those used in the PP5020 USB initialisation - if
this does turn out to be the same controller as the previous generation
I don't yet know which GPIO is used for data transfer and connection
status. For now I am concentrating on the LCD.

Cheers

Robert
Received on 2009-07-13


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