May 15th 2005
Archive for May, 2005
May 15th 2005
Flash2Advance Parport Client
When i started developing for the GBA i bought a Flash2Advance because the MBV2 limited me too much. I took the Parport version, because i thought it’s more likely to find a Parport driver or client tool for Linux than a usb based. But the only Linux based tool i could find was the Usb client called f2a. So i decided to write my own client or user space driver. I took the Usb sources and added Parport support. I used Wine to reverse engineer the protocol. I took me 2 weekends to analyse the Wine io debug dumps and find all patterns. I even had to write some Python scripts to get worked through the whole io debug logfiles. But finally i had a working parport driver. Later i ported the Parport io code from outb/inp calls to Kernel parport dev interface. The whole tool was later integrated into the Ucon64 suite.
May 12th 2005
Loundness filter for BlueMp3
I wrote an extension to the BlueMp3 firmware. Now you can use an loudness filter on the mp3-player. After reading the VS1001 specs, the BlueMp3 mp3-decoder, i noticed that it’s possbile to upload code to the dsp.This code can manipulate the current mp3 stream, so perfect for a loundness filter. I worked through the VS1001 application note and wrote some routines to upload that VS1001 code to the chip. Then i integrated that routines into the BlueMp3 firmware. There is patch available for the 1.8 firmware but also the binary 2.5 firmware includes the loundness filter code.
May 12th 2005
K2send - Gui for BlueMp3
After reading the CT article about the BlueMp3 player, i knew i need this piece of hardware. It’s an bluetooth mp3 player based on the Atmel Mega128 cpu. The firmware source is available and the client is linux based. So what do i need more to play around? I ordered the pcb and parts at Segor. The Bluetooth module and the Atmega was pre-solderd, because it’s not easy to solder TQFP’s at home. The thing was build after a hour of soldering and worked perfect. But the bluetooth signal just worked over 5 meters. So i added an Lambda/4 antenna (thanks tobi) to the bluetooth module, which extented the coverage up to 20 meters. But what i really needed was a GUI to play my mp3s. Since iam KDE user i deciced to programm my own Gui called k2send. I setup a project page a berlios for it.
May 12th 2005
I LUV SNES
I always loved the SNES. For me it was the last piece of hardware on which i enjoyed gaming. Nothin hit me again like Mario Kart or Yoshis Island. But that’s a different story.
Since my Amiga 500 days i loved to programm in ASM, but never really had the opportunity to code lately,since x86 ASM is really awful to code. But 68000er ASM was always fun. So the SNES could be a good target? Yep ! The Snes uses a pimped up 6502, called 65816. It’s faster, uses 16-bit operations and has 24bit address space. To get some code running on the SNES i used the WLA Assembler. So what does is look like ?
init_plane_0:
ldx.w #plane_0 ; assign vram location $1000 to $2116/7
stx $2116
ldx #$0000
init_plane_0_loop:
lda.w text_0,x ; get ascii text data
and #$3f ; we only want the first 64 characters
; convert ascii to c64 screen code
sta $2118
stz $2119 ; clear unwanted bits, no h/v flipping
inx
cpx #$0400 ; transfer entire screen
; $20*$20=$0400 (1024 bytes)
bne init_plane_0_loop
Yo, old skool. So i started to write a little Amiga Cracktro Style demo. I setup my devel enviroment using the WLA Assembler and vanilla Makefiles. Since i didn’t get my Super Wild Card Backupstation working, i tested the code against ZNES Emu. Also i wrote some python scripts to generate sine tables and copper bar includes. I made some color gardients with GIMP and converted then into asm includes to use then as raster interrupt lookuptables. Hm i think it took me week from start reading the 65816 specs, till i had this little thingy running. It’s far away from optimal code. Sometimes it’s jerking and no sound also. But so what, my first SNES release and iam proud that i got something runing on that machine. Learned how use HDMA tables and about Nintendo’s weired memory map (what is a zero page ???never had an C-64)….So what did come out? Have look at it.
May 12th 2005
AVR Matrix? Who needs a VU-Meter for XMMS ?
Not me? Just did some more or less useful stuff with my STK-500 dev boad. I took 64 leds and formed a 8×8 matrix out of them, solderd them onto 2 layers of ciruit boards. The leds are connected to 2 8Bit IO-Busses of an Atmel AT90S8515. I use one bus to select a row and the other bus to write on byte into a led-row. since iam changing the rows very quick, you won’t see an flicker. actually it’s 100hz refresh rate.
Then i a wrote a litte library in C using AVR-GCC to access the matrix like an framebuffer. Also funny stuff like scroll text is included in that lib. On top of this a wrote some code to interface the Atmel to PC’s serial port. That incoming data from the SIO get’s displayed on the led matrix. So that an echo “\xFF” > /dev/ttyS0 on the linux box will light up one row of the led matrix.
Last but not least i took a XMMS template plugin. Reworte it so the level output of the vu-meter is cutted down to 8 values. These values get sent to the PC’s serial interface.that’s it.
