I cut a piece of black plexi glass and drilled the holes.
Got my new prototypes in today :)
I am pleased to announce that www.JerTechOnline.com now has its own forum!
Check it out!
Even has a photo gallery
Uart boot has now been figured out on the LX
looks like the pad thickness has changed from the didj to the lx
Maybe to reduce to the cost per board? Less surface area to plate?
sd pins and cart detect have longer pads now?
before this was only for the power pads
Pad size comparison, same magnification used on the microscope and angle
After a ton of probing and trace fallowing I have come up with this schematic :)
M14 is the piggy backed roms only one side of the pins of the chip are used
IC2 is the TM5200
Table of WTF magic
now for power im using this circuit
work fine with my arduino, now to get to coding and building an small amp for the sound out
I acquired a Ti speech synthesizer module today cheep to experiment with :)
According to this old data sheet I found of the speech chip TMS5200.pdf this should be easy to interface to a Didj or arduino!
Oddly there is a second rom chip stacked on top of the original in parallel with all pins soldered to??
So I took the unit apart and removed the connector carefully to reuse it.
cleaned up the pads and lightly filed the board to fit the connector.
then carefully modified the connector so it would slide onto the board better
Next: power and bus management
|1||VCC||+5 Volts power supply||2||SBE||Low if addr in >9000-94xx (sound port)|
|3||RESET*||System reset (active low)||4||EXTINT*||External interrupt (active low)|
|5||A5||Address bus, bit 5||6||A10||Address bus, bit 10|
|7||A4||Address bus, bit 4||8||A11||Address bus, bit 11|
|9||DBIN||Active high = read memory||10||A3||Address bus, bit 3|
|11||A12||Address bus, bit 12||12||READY||Active high = memory is ready|
|13||LOAD*||Un mask able interrupt (=> BLWP @>FFFC)||14||A8||Address bus, bit 8|
|15||A13||Address bus, bit 13||16||A14||Address bus, bit 14|
|17||A7||Address bus, bit 7||18||A9||Address bus, bit 9|
|19||A15||Address bus, lsb. Also CRU output bit.||20||A2||Address bus, bit 2|
|21||GND||Ground||22||CRUCLK*||Inversion of TMS9900 CRUCLOCK pin|
|23||GND||Ground||24||PHI3*||Inversion of phase 3 clock|
|25||GND||Ground||26||WE*||Write Enable (derived from TMS9900 WE* pin)|
|27||GND||Ground||28||MBE*||Active low if addr in >4000-5FFF (card ROMs)|
|29||A6||Address bus, bit 6||30||A1||Address bus, bit 1|
|31||A0||Address bus, bit 0 (most significant)||32||MEMEN*||Memory access enable (active low)|
|33||CRUIN||CRU input bit to TMS9900||34||D7||Data bus, bit 7 (least significant)|
|35||D4||Data bus, bit 4||36||D6||Data bus, bit 6|
|37||D0||Data bus, bit 0 (most significant)||38||D5||Data bus, bit 5|
|39||D2||Data bus, bit 2||40||D1||Data bus, bit 1|
|41||IAQ||Interrupt acknowledged by TMS9900||42||D3||Data bus, bit 3|
|43||VDD||-5 Volts power supply||44||AUDIOIN||To sound generator AUDIO IN pin|
Yes we now have a working gameboy advance emulator working on the LX!
sound is a bit messed up on some games but its a start!