#114734 - PTH - Wed Jan 10, 2007 3:06 pm
Afternoon all,
So - I'm about to embark on a project with my DS, and I was wondering if someone could clear up a few questions for me before I go start spending cash...
--- If you're not interested in the background, skip this bit... ---
I'm aiming to use my DS as a dashboard mounted controller for a Car PC that's currently in development. Having looked at in-dash VGA touchscreens, etc. (~ UK?200), I've realised that with a little homebrew, and a fair bit of hardware hackery, my DS would be perfect for the controller. Now I've just got to make it work.
--- The Questions ---
Q1 - I need a method of running homebrew...
Looks like the M3 Simply is the right card for me, from an extensive google research campaign. Anything I should know before I spend the cash?
Q2 - GBA SRAM interface.
Just to check I've got this straight... The GBA cartridge interface includes a straight SRAM interface which presents a 16-bit address on pins 6-21 (From http://www.hardwarebook.info/Game_Pak). By reading specific addresses on the SRAM range (mapped as 0x0A000000 - 0x0A00FFFF), I can manipulate the levels on these pins.
Sticking a PIC or similar on the other end should let me sort out a fairly basic interface (anyone know the voltage levels that come out of the SRAM interface?).
As I'll be using a slot-1 card, slot-2 should be free to allow me to use these pins?
(For the record, I'm aware of the DSSerial and similar devices, but they need a specific bit of kit in slot-1... I'm also happy doing line-level conversion, building an intermediate PIC, etc. so an "all-in-one-just-plug-in" solution isn't really important to me. And it has to be cheap. Real cheap :) )
Q3 - Getting at the GBA interface
The slot-2 blanking card that came with my DS lite would seem to be ideal to hack about for this... Anyone know where I could buy a spare? Otherwise, I guess it's down to buying the cheapest GBA game I can find and taking it to bits.
Q4 - In order to make all this work, I need my DS to talk to an external microcontroller... Lots of folks on this forum seem to use Atmel parts, though I was planning on using a PIC - Anything I should be aware of? Thinking about it, are there any atmel parts with multiple UARTs on board? Would make life easier if I had spare serial ports to talk to GPS, mobile phone, etc.
Q5 - I'm going to need to build a cradle for my DS... Anyone know of any accessories that could be used as a good starting point for this, or am I on my own? This is probably the piece of the project I'm most likely to screw up :)
That's the lot then. Thanks in advance to anyone helping me out... If anyone else is interested in seeing the results (it may be a while), let me know, and I'll sort some kind of blog for the project.
Cheers again,
Pete
So - I'm about to embark on a project with my DS, and I was wondering if someone could clear up a few questions for me before I go start spending cash...
--- If you're not interested in the background, skip this bit... ---
I'm aiming to use my DS as a dashboard mounted controller for a Car PC that's currently in development. Having looked at in-dash VGA touchscreens, etc. (~ UK?200), I've realised that with a little homebrew, and a fair bit of hardware hackery, my DS would be perfect for the controller. Now I've just got to make it work.
--- The Questions ---
Q1 - I need a method of running homebrew...
Looks like the M3 Simply is the right card for me, from an extensive google research campaign. Anything I should know before I spend the cash?
Q2 - GBA SRAM interface.
| Quote: |
|
You can "misuse" each line of the slot 2 parallel interface as a serial interface by doing a sequence of reads from specific SRAM addresses. There is a slow enough rise time on the SRAM address lines that this will work. I have used this method to create a SPI interface from four of the parallel lines. (From http://forum.gbadev.org/viewtopic.php?t=12098) |
Just to check I've got this straight... The GBA cartridge interface includes a straight SRAM interface which presents a 16-bit address on pins 6-21 (From http://www.hardwarebook.info/Game_Pak). By reading specific addresses on the SRAM range (mapped as 0x0A000000 - 0x0A00FFFF), I can manipulate the levels on these pins.
Sticking a PIC or similar on the other end should let me sort out a fairly basic interface (anyone know the voltage levels that come out of the SRAM interface?).
As I'll be using a slot-1 card, slot-2 should be free to allow me to use these pins?
(For the record, I'm aware of the DSSerial and similar devices, but they need a specific bit of kit in slot-1... I'm also happy doing line-level conversion, building an intermediate PIC, etc. so an "all-in-one-just-plug-in" solution isn't really important to me. And it has to be cheap. Real cheap :) )
Q3 - Getting at the GBA interface
The slot-2 blanking card that came with my DS lite would seem to be ideal to hack about for this... Anyone know where I could buy a spare? Otherwise, I guess it's down to buying the cheapest GBA game I can find and taking it to bits.
Q4 - In order to make all this work, I need my DS to talk to an external microcontroller... Lots of folks on this forum seem to use Atmel parts, though I was planning on using a PIC - Anything I should be aware of? Thinking about it, are there any atmel parts with multiple UARTs on board? Would make life easier if I had spare serial ports to talk to GPS, mobile phone, etc.
Q5 - I'm going to need to build a cradle for my DS... Anyone know of any accessories that could be used as a good starting point for this, or am I on my own? This is probably the piece of the project I'm most likely to screw up :)
That's the lot then. Thanks in advance to anyone helping me out... If anyone else is interested in seeing the results (it may be a while), let me know, and I'll sort some kind of blog for the project.
Cheers again,
Pete