August 25 2010

Didj vs LX cart diferences

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

Category: Didj, Electronics | LEAVE A COMMENT
August 21 2010

Arduino Enclosure Modding

Before:

Notice how the surface isn’t smooth with the plates in.

After:


How did I do that?
First I used a layer of plastic model glue to secure the panels in place. Once the glue had dried I sanded as much as i could to make the panels flat with the case surface. first with course sand paper 40 grit then move my way up slowly to 250 grit.
Next I applied a layer of primer paint. let it dry then sanded it down with 250 again.I then applied some epoxy to the cracks with a razor blade to make sure that the surface was as smooth as possible. sanded smooth then applied another layer of primer. once the primer was dried for a day i took some very fine wet sand paper and wet sanded the case till it was super smooth.
now it looks like there were never panels to begin with :)

Category: Arduino / AVR, Electronics | LEAVE A COMMENT
August 12 2010

Speech Synth Reverse Engineered

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

Category: Arduino / AVR, Didj, Electronics | 4 Comments on Speech Synth Reverse Engineered
August 11 2010

Pins used by the speech module

1 VCC +5 Volts power supply 2 SBE Pin 2 74LS138 B input
3 RESET*
Pin 6 74LS138   G1
4 EXTINT* Not Used
5 A5 Pin 1 74LS138  A input 6 A10 Not Used
7 A4 Not Used 8 A11 Not Used
9 DBIN Not Used 10 A3 Not Used
11 A12 Not Used 12 READY Active high = memory is ready
13 LOAD* Not Used 14 A8 Not Used
15 A13 Not Used 16 A14 Not Used
17 A7 Not Used 18 A9 Not Used
19 A15 Pin 5 74LS138  GB2 input 20 A2 Not Used
21 GND Ground 22 CRUCLK* Not Used
23 GND Ground 24 PHI3* Not Used
25 GND Ground 26 WE* Not Used
27 GND Ground 28 MBE* Not Used
29 A6 Not Used 30 A1 Not Used
31 A0 Not Used 32 MEMEN* Not Used
33 CRUIN Not Used 34 D7 Pin 1 TMS5220
35 D4 Pin 22 TMS5220 36 D6 Pin 26 TMS5220
37 D0 Pin 14 TMS5220 38 D5 Pin 24 TMS5220
39 D2 Pin 12 TMS5220 40 D1 Pin 13 TMS5220
41 IAQ Not Used 42 D3 Pin 19 TMS5220
43 VDD -5 Volts power supply 44 AUDIOIN Pin 8 TMS5220
Category: Electronics | LEAVE A COMMENT
August 11 2010

TI Speech Synch Exploring

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
Category: Didj, Electronics | LEAVE A COMMENT