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The MFC5249 User's manual is quite daunting at 450 pages and the HD667733R at 133 pages too. I just need a little help!
The LCD command register and data register are listed in the twiki as 0x20008000 and 0x20008002 repectively but the driver writes to 0xF0008000 and 0xF0008002. Why this descrepancy?
How is the mapping of the LCD chip to CPU memory addresses accomplished? Is it hardwired on the board or done in the software somewhere? Which lines? Knowing this would help my understanding of the CPU greatly.
Which interface does the LCD driver use? I know it's 18-bit but serial or parallel?
As far as full color support goes, I seriously wouldn't mind *gasp* wasting the memory and just using 32 bits per pixel for simplicity and speed. The memory requirement would only be doubled. It can also be dithered easily enough if someone wants super high quality.
I've read a request on another thread about shutting down the LCD panel when the backlight is off. ... Is it even worth it?
The default value of CS2 (a "segment" register) is 0x20000000, also used by the OF. RB uses 0xF0000000, hence all memory addresses in this area (LCD, IDE, USBOTG) are rebased.
backlight is off after 5 seconds w/o keypresses (actually I want a fade-out )
Also, you should check out the HWM (sp?) mode that allows 4 aligned LCD writes to be done in parallel. It probably requires changing the direction the framebuffer is stored, but maybe it's faster.
I want LCD to be shut down gracefully on player shutdown.
Can you tell what pins are involved in the addressing? That would help me understand the CPU better in general as far as hooking up external devices. I do care so! Grin
The lcd_x5.c is easy to understand in general. I'm curious about that burst RAM write stuff. It says you have to write four words (goes into registers) and writes that to GRAM while you write the next four words.
Why is there no backlight dimming? That thing eats power and it doesn't need to be fullbright when looking at the WPS or browsing.
In fact, I tried to open the firmware in IDA, but I don't really know which segments to create. HuhI do see functions and data (e.g., strings, CRC-16 lookup tables, ...) but I cannot resolve absolute addresses.I saw http://www.rockbox.org/twiki/bin/view/Main/IaudioPort#Original_firmware_information, but I just don't understand what exactly is considered ROM, RAM, "ports", etc. (what are IRAM and GPIO anyway?)
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