NES controller on PC Engine / TurboGrafx 16

My brother needed a second controller for his PCEngine so we could co-op some shmups but original controllers are wildly expensive! And even if you find a cheaper option from another region, you'll need to buy yourself an adapter...ugh. So what I was design a circuit board to implant into an NES controller shell!

Easy as pie. This board supports either the cord for a PCengine or a turbografx and has broken out headers in case you want to install it into a different (larger) controller shell. This version does not support turbo buttons right now though.

Top Side:

Back Side:

Once I print some, I'll update with another post. 

Gameboy Camera Force Trippy H

Here is something I have been working on for a few days now and only got a little bit of progress. But progress is progress and this really helps me understand gameboy debugging.

Analyzed the WRAM addresses for any and all changes that occur when you press buttons, select particular cursor locations and of course: when you enter DJ mode (Trippy H).

After hours and hours, I found that WRAM $D5CE is the game mode byte, or at least that's what I call it. This byte is changed directly before switching between dancing mario, menu, view, shoot and trippy H (as well as the other menus and modes).
1:D5CE 00 w
The first instance was when you press a button while mario dances. I restarted the emu and pressed A. The code broke and stopped at $74AC where there was an "LD A, $00"
Has someone done this before?

Dance = 19, menu = 00, shoot = 01, DJ = 1F, view = 02, play - 07, etc.

After learning this, I set an access break when the byte 00 is written to $D5CE

I replaced this with "LD A, $1F" and restarted again.

This time when you press a button at dancing mario, Trippy H starts!

----------------------------------------------------------------------------------------------------------------

Next update I would like to stop the cart from checking if the camera is present. This will allow the ROM to be put onto a normal flash cart. 

2nd future update would be to remove unnecessary routines like "shoot  " and "view" hopefully the ROM itself can be reduced in size. Potentially an MBC1 + SRAM + BATTERY

3rd future update I would like to break the ROM even more and remove saving altogether so that it can be safely put on a 64M cart along with LSDJ or a dedicated ROM only cart.

ROM, EPROM, EEPROM that I like

Here is a quick-check list of different roms that are easy to get.

All run on single supply voltages of 5v and are accessed via a parallel bus.
Also listed is what to do with those pesky control pins when if you just want these to be read by the controlling system (NES, Genesis, z80, etc)

8-bit UV Eproms:

27c16 - 2,048b x8 = 2 KBytes 

27c32 - 4,096b x8 = 4 KBytes

27c64 - 8,192b x8 = 8 KBytes 

27c128 - 16,384b x8 = 16 KBytes

27c256 - 32,768b x8 = 32 KBytes

27c512 - 65,536b x8 = 64 Kbytes

8-bit EEPROMs:

29f010 - 131,072b x8 = 128 KBytes alt: 29ee010, 49f010

29f020 - 262,144b x8 = 256 KBytes alt: 49f020

29f040 - 524,288b x8 = 512 KBytes alt: 49f040

8- or 16-bit UV EPROMs:

27c400 - 512Kb x8 or 256Kb x16

27c800 - 1Mb x8 or 512Kb x16

27c160 - 2Mb x8 or 1Mb x16

27c322 - 2Mb x16 (no 8-bit mode available)

8- or 16-bit EEPROMs:

29f200  -  256Kb x8 or 128Kb x16 (~1.64usd ea)

29f400 - 512Kb x8 or 256Kb x16 (~2.11usd ea)

29f800 - 1Mb x8 or 512Kb x16 (~3.12usd ea)

29f160 - 2Mb x8 or 1Mb x16 (price unknown)

8-bit EEPROMs I am looking into:

29- or 49-f040  - 512Kb x8
29f080  -  more info once I use them
29f016
29f032

There are of course hundreds of other roms, but I don't use them.

Control Pins:

None of these pins can be left hanging (disconnected) as far as I know. So don't do it.

Note: "!" will be used to distinguish low-enable pins. This means that when this input is pulled low, the function is enabled.

!CE - Chip Enable, AKA !E:
Most likely your system will need this to be connected to the control bus of the system. Sometimes it is connected to GND directly if your system has NO other memory that it must address. Sometimes it is connect to !OE, but only if your system has no other memory to access.

!WE - Write Enable. AKA !WR:
Typically your system will not be able to program the rom, so this should be pulled high by a resistor connected to vcc. Sometimes you can get away with connecting this pin directly to vcc without a resistor. Anywhere between 4k7 to 10k ohms should be good.

!OE - Output Enable. AKA !RD, !G:
Most likely your system will need this to be connected to the control bus of the system. Sometimes it is connected to GND directly if your system has NO other memory that it must address. Sometimes it is connect to !CE, but only if your system has no other memory to access.

!PGM - Program Enable:
This is similar to !WE but is only seen on a select few ROMs that also require a VPP voltage. Connet this pin to vcc inside your system.

VPP - Programming voltage:
This is typically a high voltage of 12v to 21v required to program a UV EPROM. This is not going to be used by your system, so it should always be pulled high/VCC/+5v.

!OEVPP - Output Enable / Programming voltage
When low (0v), this pin acts as the data output enable pin. When high (vcc) this pin shuts off data output. When connected to vpp (typ. 12v - 21v) this pin acts as vpp putting the chip into programming mode. Connect this pin to your control bus as though it were just !OE.

Q15A-1 - This pin is very special! When in 16-bit mode (byte pin high), this pin is used as data pin D15 or Q15.When in 8-bit mode (byte pin low), this pin is Address pin minus 1. And yes, by minus 1, this is less than 0. What that means is, the pin will connect to A0 on your computer's bus, eprom pin A0 will then connect to computer side A1, etc. here is a little diagram:

rom ---- computer
A-1 ---- A0
A0 ----- A1
A1 ----- A2
A2 ----- A3

!BYTEVPP - Byte Mode / Program Supply:
This pin is pulled high if using the rom in 16-bit mode, or ground when in 8-bit mode.
When this pin is connected either to VSS or VCC, then VPP is ignored, The only time the VPP function is used is when the voltage connected is 12v to 21v as instructed by the appropriate datasheet.
Further explanation from a datasheet:

The M27C160 (for example) has two organisations, Word-wide and Byte-wide. The organisation is selected by the signal level on the BYTEVPP pin. When BYTEVPP is at VIH the Word-wide organisation is selected and the Q15A–1 pin is used for Q15 Data Output. When the BYTEVPP pin is at VIL the Byte-wide organisation is selected and the Q15A–1 pin is used for the Address Input A–1. When the memory is logically regarded as 16 bit wide, but read in the Byte-wide organisation, then with A–1 at VIL the lower 8 bits of the 16 bit data are selected and with A–1 at VIH the upper 8 bits of the 16 bit data are selected.

For a much more in-depth explanation of eproms, see:
https://wiki.xtronics.com/index.php/How_EPROMS_Work

Odyssey 2 variety cart

I am also currently working on a flash cart for the Odyssey 2 that supports a wide array of roms, proms, eproms, etc.

27C-, 28F-, 29F-, 29EE-, 49F-, etc.
16, 32, 64, 128, 256, 512, 010, 020, 040, and maybe more.

SwinSID SE - reworked by Me

Been toying with the SwinSID which is a decent DIY version of the SID chip. My version takes up no more space than the original and would be a drop-in-replacement with no extra wiring. Programming the atmega would be a little difficult though since there is no room for an ICSP.

SMS variety Cart

Currently working on a flash cart for the SMS that supports a wide array of roms, proms, eproms, etc.

27C-, 28F-, 29F-, 29EE-, 49F-, etc.
16, 32, 64, 128, 256, 512, 010, 020, 040, and maybe more.

Problem is ... I don't own a Master System to test these out. I will not be printing any until I get one.

Composite Video from the Nintendo Gameboy

My latest project is to get some sort of video output from the nintendo gameboy. The signals are all present, but are not in a form that can be connected to any television or monitor. My first thought is to convert the signals into a single analog signal called composite video.

Composite video is named as such because it contains color data (chroma), brightness (luma) and synchronization on wire.

1. Chroma is not important in this case becuase the gameboy is monochrome. All of the color differences will be made with Luma.

2. Luma: As above, the Luma will be used to create our four different colors. The TV looks for an analog signal here. The gameboy has two data pins which are used for this purpose, so connected through a DAC of some sort, we can create four different levels rather than just 0v and 5v.

3. Sync
 Csync or composite sync is an XOR of horizontal and vertical sync. These two signals tell the television to move down one line or to move back to the top of the screen. I am not quite sure how progressive or interlaced are determined by these just yet.

Next, these have to be connected together over one wire. As mentioned, the luma is an analog value but what I forgot to mention was that it is a positive signal whereas sync is negative. From what I have read, composite must be AC coupled because the TV input is DC coupled. That being said, our sync can actually be positive as well, as long as the luma is offset by DC value. Once the signal goes into the TV, the DC coupling circuit will block the average DC offset which is our black level. Black level will become 0 volts inside the Tv so sync will become 0v to -0.4v and Luma will be between 0v and +0.7v.

I am not at liberty to share my schematic at this point but it doesn't' work that well anyhow. :P
As a first attempt however, the result is quite promising.

You will notice that the image scrolls in several directions and that it is repeated three times over from left to right. I believe this is a problem with synchronization and possibly the LCD itself.

Updates to follow shortly. 

Miracle Piano Final Thougts

I finally had time to probe a few pins inside the Miracle Piano.

AS0012 - Pin 21 (PWM)
It turns out this pin controls the master volume and NOT the envelope as I had originally assumed.
Turning on the keyboard, this pin defaults to about 50%, but as you can see, it is not exactly 50%. How odd.
When the volume is reduced, the pulse width is widened and when the volume is increased, the pulse width is reduced. That is because the integrator, U4A is inverting the output.

Each photo has the scope set to 10 microseconds per division:

Default Volume:



Highest Volume:



Lowest volume:



U4 - Pin 1
This pin goes to the LM13700 to control the master volume, or gain of the sound. It appears as a DC voltage and is remarkably solid. There is no visible ripple as would be expected from an integrator.
No photo is needed of this signal.

J004 - Pins 21-24 (OUT1-OUT4)
The signals from these pins are too small to view on my scope, so I chose the amplified versions from U10. Pins 1, 8, 7 and 14 respectively.

OUT1 is not active for all sound samples, apparently. When Harpsichord and Synthesizer are selected, nothing comes out at all.
When the other four sounds are selected however, the waveform is perfectly clear.

OUT2 is the opposite. Only when Harpsichord and Synth are selected, do we see any activity on this pin.

OUT3 mimics OUT1 exactly, or at least as far as I can tell.

OUT4 on the other hand does not seem to react to any button or key. It simply outputs a DC voltage which measures 5.03v at pin 14 of U10.

I can speculate as to why there are three OUT pins. While probing both Pins 8 and 14 of U4 which has the mixed and filtered outputs split to both left and right output terminals, the waveforms are identical for Harpsichord and Synthesizer but are not identical for the other four sounds. It would seem that Harpsichord and Synthesizer were recorded and digitized in mono while the other four sounds were recorded and digitized in stereo.

I am a little saddened that the envelope is not broken out to any specific pin or sub-circuit.

Some other Notes

J004 - Pin 40 (Bus Strobe)
This pin reacts differently for different sounds, however, when the key is pressed with a sound that has an attack and release; the pin will strobe for the full length of the sound and go to 0 when the note is finished.
For a sound that ends only when the key is released, the pin strobes at key press for a moment, then goes to 0 and strobes once again when the note is released.

I could use this pin for creating a gate and trigger, but it would require that I charge a capacitor then feed it through a comparator and set up some logic to keep the signal high when the key is pressed and low when the key is released. This wouldn't require too much effort, but the function would change from sample to sample since the envelopes are all different. I don't thin the modification is worth it in this case.

"Piano" sample is very hard to photograph since the amplitude changes so rapidly in software. It looks very similar to "Organ, but is more rounded whereas the Organ is more triangular.


"Organ:"



This photo shows a sample that is identical on both sound channels. Trust me, they are identical but the channels are not being displayed the same way.


These two photos show sounds that are not identical from OUT1 and OUT2.



PS: Yes, the reflection in my oscope is naked. Deal with it.

min64 - The bare minimum rom cart for commodore 64 - part 2

The boards arrived but I have yet to test them out.

min64 - The bare minimum rom cart for commodore 64

The idea was to design a cart that would fit entirely in the commodore without sticking out. Surprisingly, it could even be made small enough to fit a shell, if I make one in the future.

The board has has one ROM and thats it.








The board is a meer 1.05 inches deep and has notches for easy removal or mounting (granted a shell is designed). Measuring my own commodore, a board of 1.1875 inches would be flush with the chassis. Also has optional reset switch as suggested by catskull.

My main concern was supporting as many proms, eproms and eeproms as I could since too many are no longer made, but easy to find.

Those supported include:

28F010, 28F020, 28F040,
29F010, 29F020, 29F040,
49F010, 49F020, 49F040
2764, 27128, 27256, 27512
27c64, 27c128, 27c256, 27c512

As well as SF's, GL's, EE's, etc.

Also working on support for 2704, 2708, 2716, and 2732. These will fit, but would require a few rerouted pins.

In any case, I can't wait for these to arrive from OSHpark.

CCAM - Crystal Clear Audio Mod for Sega Genesis/MegaDrive by Tiido

I took an afternoon to look at Tiido's circuit to clean up and amplify certain channels on the poorer created versions of the Sega Genesis and megadrive. This circuit separates all of the audio channels, amplifies them individually, mixes, amplifies again, offsets the DC output and applies a low pass filter. This is based on the sound filter inside of the original "HD Graphics" models of the sega genesis which arguably has the best sounding output.

I have taken the liberty of redesigning the circuit with all higher quality 1% tolerant, through-hole components, a low power op amp and easy to solder tie points for installation.

Fun with the Sega Genesis - Ultimate Portable Game player

Found a crazy deal on fleabay for one of these and had to have it. I had heard stories of how badly they are made, and how miserable the audio is.
All very true, but I think it can be improved a little.

The video is great, the size a too small, the sound from the speaker is crap but the sound from the headphone could be worse.
I immediately took it apart after opening the box. I was THRILLED to see only one epoxy-chip and several SOP's! :D

I want to believe that the audio issue is because of the amp/filter they have used. Through headphones, it sounds ok, but also a little clipped and shallow. This could also be because of the power supply, which is very weak. The battery is 3.7v and droops when the PSG is loud.




Its like a portable MP3 player considering all the titles that have sound tests. :p
You know, except horrible sounding.

Do not stay at the Guest Quarters Hotels - Dumping The Miracle Piano Teaching System

I had my Willem programmer pulled out for some Sega Genesis programming stuff and decided to finally dump the eprom inside of the Miracle Piano teaching System Keyboard. If you recall from a previous post of mine, it contained a 27c256 OTP eprom. It also contained many proprietary ICs of which I may never figure out. We may never know what microcontroller they used or what language the machine code is suppose to be written in. z80, 6502, etc.

In any case; with many vintage computers and other devices containing ROM, the authors always find the space to sign and date their work and in rare cases they may even decide to add a little easter egg. Although I cannot locate a date, here is some clear text I found in the ROM image:

"This Eprom contains code created by Mike Collins. Anne Graham and Ray Livingston. Do not stay at the Guest Quarters Hotels. Keep that Coke classic and that Piping hot coffee coming."



I got a real kick out of reading that. For anyone who knows what to do with it, here is the binary file:
http://www.mediafire.com/download/eo3zujca7jvw44f/MPTS_ROM.zip

Intec PS2 LCD screen Mod

I found a controller at a junk shop for $5, and figured I would mod it onto a console. For the longest time I couldn't figure out how to add it to a console because I didn't know which cable was which. Now I figured it out: Orange: +12v (connects to a 7808 regulator so the voltage range should be greater and lesser than 12.) Black: Ground Brown: Ground Red: Right Audio input White: Left Audio input yellow: Composite video input Now I can finally build it into something. Maybe my new Sega Genesis 3, since it will fit right on the face of it and hopefully can share the same +10v power supply!

Arduino - Cast Int to Byte - What happens?

For a project I need to spread a 16-bit unsigned integer across one byte variable and two 1-bit variables, all of which will be written to pins. The reason is not important, but I needed to know what happens to the byte value when I cast it to the byte variable. I understand that it will be truncated, but what will? The higher 8-bits or the lower 8-bits?

To find out, I wrote a quick program with a lot of clear text output.

// cast test by Jordan
// Test truncation of variables from one type to another
// most importatntly: int to byte

unsigned int intVar = 0x4080; // will it truncate to 01000000 or 10000000?
byte byteVar = 0x33;
void setup(){
  Serial.begin(9600);
  Serial.print("hello world.");
  Serial.println();
  Serial.println();

}

void loop(){
  Serial.println("integer variable equals: ");
  Serial.println(intVar, BIN); // print variable in binary
  Serial.println();
  Serial.println("byte variable equals: ");
  Serial.println(byteVar, BIN);
  Serial.println(".");
  Serial.println("..");
  Serial.println("...");
  byteVar = (byte)intVar;
  Serial.println("byte variable now equals: ");
  Serial.println(byteVar, BIN);
  while(1){} // loop forever
}

Then I uploaded it to my Arduino Nano and opened the serial monitor. I then uploaded it to my Teensy 2.0 to double check the code across platforms. Teensy is a little different in some aspects, so I had to make sure. They both output exactly the same thing:

Serial monitor output:

"hello world.
integer variable equals:
100000010000000
byte variable equals:
110011
.
..
...
byte variable now equals:
10000000"

These are the exact results that I wanted to see. I may continue on with more programming now...

EDIT: Further testing proves that the same theory does NOT hold true with booleans. (get it? "true") I had hoped that the boolean could be used to store a 1-bit number, but it turns out they are actually some sort of integer in disguise! I will have to figure out some fast way to manipulate individual bits...

Repairing an LCD Monitor

I am damn cheap, and this isn't the first time I have gotten a broken monitor to use as my own. By broken, I do not mean that the LCD is cracked, but that it comes on and goes off immediately. Some even went black and had a buzzing noise. More often than not, this means some capacitors on the power board are swollen or popped. This is just a detailing of one monitor in particular, but the method is nearly identical to other modern screens. The other problem that could occur seems less common, so I will not cover it here. The less common problem is the wires connecting to the CCLF tubes coming loose.

Step 1. Open the screen.
Unplug the monitor and press the power button a few times to (mostly) discharge any good capacitors.
Find all of the screws that are visible including VGA/DVI mounting screws and remove them, keeping a good idea of which holes they came from.

Now pry apart the plastic shell carefully. I use an expansion slot cover found on the back of a PC because they are wider than a screwdriver and leave less cosmetic damage (if any at all). Once you have the plastic bevel popped all around the edges, place the screen on your surface area, or lap, face down and lift the plastic off the back. This may not be the exact way for all monitors, but it has been for the last four I repaired.

Step 2. Take note of the orientation of the wires leading from the metal shielding. THese connecto to the high voltage CCFL tubes and may or may not be polarized. Don't screw this up! Take a photo if it helps.



Remove the metal shielding from the power and logic boards. Be very careful of any ribbon cables.
You should find the power board which is suspect.



Step 3. Inspect the power board. If you find swollen capacitors, you probably found the culprit. In our case, there are two swollen capacitors. From my experience, they normally go out in pairs, but I cannot prove that. Can you see the two fatties?




Step 4. Replace the capacitors with a "good" brand. Nichicon is my favorite. Make sure that the Farads are matched exactly and that the voltage is either the same or higher. Higher is better in this case, but normally the caps become larger with a higher voltage tolerance.



Step 5. Put it back together and power it up. ta-da! Although this is not 100% to work for you, it is a common problem and an easy fix. Good luck and good modding.

-Jordan

 ps. The monitor in this example was the Westinghouse L1975NW. I replaced two 220uF 25v capacitors with two 220uF 35v capacitors.
I also repaired an Acer x193w+ with new caps and some other Acer I no longer have.
One time I found that a Dell E2K-SE198WFPF(B) by reconnecting the CCFL tube with its wire which was difficult and apparently dangerous. To do so I had to disassemble the screen itself, LCD, polarizing film, and other layers just to get at the tubes...which were well encased in rubber. It was very difficult and I don't think that I would attempt it again.

Adding Analog Pins to Arduino pt.2

Don't forget part 1: http://jazz-disassemblies.blogspot.com/2014/01/adding-analog-pins-to-arduino-pt1.html

The first step in part 2 of adding analog pins to an arduino is by getting rid of the MCP3008! Yes, I am sorry but that particular IC is overly complicated and too expensive for what it offers.

Since I wrote that first part, I began looking for alternatives because of the price of the MCP3008. Even in quantities of 10 or more, the IC was still more expensive than a bare Atmel microcontroller! At first I thought that I could buy another microcontroller for less than the MCP3008 at a fraction of the cost and even be able to simplify the methods of communication to my own liking.

After looking for the cheapest, yet adequately powerful uC, I came across the ATtiny48 which has several Analog inputs and even more digital IO's. The Analog inputs would in theory, be read, stored in variables and then transferred to the master microcontroller across an 8-bit wide data bus. The particular analog value that would be transferred would be selected by the master uC via three other pins; select bits. The pins were going to offer a binary value which would select the current pot to be transferred.

This method would allow for me to read many many more pots than the master microcontroller was equipped with, but at a large cost; the cost of many digital IO pins. One way to get those digital IOs back would be to use analogWrite on one of the PWM outputs and connect that pin to an analog input on the master uC. Considering that, I could sacrifice one analog input for 8 more. HOWEVER, the AT48 has no PWM outsputs. :(

After mulling over it for a long time, I realized what I had actually designed. The program I had spent an hour writing... The program that utilized the exact methods of communication to suite my exact needs...was, you guessed it: An analog multiplexer which decodes 3-to-8 inputs. They have an app...I mean IC for that. The 74HC4052 accepts two sets of 4 analog inputs and connects them to one of two outputs respectively. Two select bits, choose the analog input to transfer to the output.

The 4052 is a mere 50 cents, requires no external programming, runs on a large voltage range and comes in a variety of packages!

I will simply import photos and descriptions of my project, so that I can describe how to use the 4052.
Analog pins A0-A3 are used for higher priority data, so that leaves A4-A7 open. Again, we will also need two digital IO to use as select bits on the 4052.

// ***************************************************************
// define pin connections
// ***************************************************************

int pSelect0 = 3;
int pSelect1 = 4;

// ***************************************************************
// define variables
// ***************************************************************

// locate the delay between the select bits and the updated output
// of your 4052 IC and update this value:
int latency = 100; 

byte aVal00 = 0; // analog Value, 4052 # 0, input 0
byte aVal01 = 0; // analog Value, 4052 # 0, input 1
byte aVal10 = 0; // analog Value, 4052 # 1, input 0
byte aVal11 = 0; // analog Value, 4052 # 1, input 1

byte aVal02 = 0; // analog Value, 4052 # 0, input 2
byte aVal03 = 0; // analog Value, 4052 # 0, input 3
byte aVal12 = 0; // analog Value, 4052 # 1, input 2
byte aVal13 = 0; // analog Value, 4052 # 1, input 3

byte aVal04 = 0; // analog Value, 4052 # 0, input 4
byte aVal05 = 0; // analog Value, 4052 # 0, input 5
byte aVal14 = 0; // analog Value, 4052 # 1, input 4
byte aVal15 = 0; // analog Value, 4052 # 1, input 5

byte aVal06 = 0; // analog Value, 4052 # 0, input 6
byte aVal07 = 0; // analog Value, 4052 # 0, input 7
byte aVal16 = 0; // analog Value, 4052 # 1, input 6
byte aVal17 = 0; // analog Value, 4052 # 1, input 7

// ***************************************************************

// Setup

// ***************************************************************

void setup()

{

Serial.begin(9600);

// define pin modes   

pinMode(pSelect0, OUTPUT);

pinMode(pSelect1, OUTPUT);

}  

// ***************************************************************

// Main Loop

// ***************************************************************

void loop()

{

getAnalog();

processAnalog();

}

// ***************************************************************

// Get Analog Values

// ***************************************************************

void getAnalog()

{

  // read the first set of four

  // part 1 of 4

  digitalWrite(pSelect0, LOW), digitalWrite(pSelect1, LOW); // 00

    delayMicroseconds(latency);

  

aVal00 = map(analogRead(A4), 0, 1023, 0, 255),

aVal01 = map(analogRead(A5), 0, 1023, 0, 255),

aVal10 = map(analogRead(A6), 0, 1023, 0, 255),

aVal11 = map(analogRead(A7), 0, 1023, 0, 255);

  

  // read the second set of four

  // part 2 of 4

  digitalWrite(pSelect0, LOW), digitalWrite(pSelect1, HIGH); // 01

    delayMicroseconds(latency);

  

aVal02 = map(analogRead(A4), 0, 1023, 0, 255),

aVal03 = map(analogRead(A5), 0, 1023, 0, 255),

aVal12 = map(analogRead(A6), 0, 1023, 0, 255),

aVal13 = map(analogRead(A7), 0, 1023, 0, 255);

  

  // read the third set of four

  // part 3 of 4

  digitalWrite(pSelect0, HIGH), digitalWrite(pSelect1, LOW); // 10

    delayMicroseconds(latency);

  

aVal04 = map(analogRead(A4), 0, 1023, 0, 255),

aVal05 = map(analogRead(A5), 0, 1023, 0, 255),

aVal14 = map(analogRead(A6), 0, 1023, 0, 255),

aVal15 = map(analogRead(A7), 0, 1023, 0, 255);

  

  // read the last set of four

  // part 4 of 4

  digitalWrite(pSelect0, HIGH), digitalWrite(pSelect1, HIGH); // 11

    delayMicroseconds(latency);

  

aVal06 = map(analogRead(A4), 0, 1023, 0, 255),

aVal07 = map(analogRead(A5), 0, 1023, 0, 255),

aVal16 = map(analogRead(A6), 0, 1023, 0, 255),

aVal17 = map(analogRead(A7), 0, 1023, 0, 255);  

  

  

  return; // return to main loop    

return;

}

// ***************************************************************

// Process the values

// ***************************************************************

void processAnalog()

{

// Do whatever you would like to do with the values here

return;

}

// ***************************************************************

That is all. I realize that the getAnalog function could be simplified using an array, but I did it quickly. If anyone wants to make that change, please share it! Also, I used the map function to change the analog value that was read from 10-bits to 8-bits. I have my reasons, but anyone may remove that if they want a higher resolution. 

There you have it. 16 independent analog values on top of the 4 I needed for something else. With all of the analog pins at our disposal, you could have 32 analog values! I am using this for 16 pots and the other 4 for external control voltages. Just imagine, 32 analog values with a simple Atmega168. 

Keep up with future posts to see when I actually breadboard this out. 

Update: Sega GameGear CPLD Cartridge(s)

Just an update for an old post I made.

http://jazz-disassemblies.blogspot.com/2013/09/gamegear-cpld-cartridge.html

Remember the Flash cart that Majesco made with a CPLD as the mapper? Well, I tried again to get a pirated ROM to run in place of the old Caesar's Palace ROM and it refuses to!

Dumping the Binary for Caesar's Palace, it is an exact hex match with the copy circulating on the internet, so I know whatever mapper is contained on the CPLD must at least support ROMs up to 256 KBytes, because Caesar's Palace is that large. I tried the Fan translation of Phantasy Star Adventure which is only 128 KBytes and it will not run. I even duplicated it across the full capacity of the flash ROm just in case one of the higher address bits was tied to something I didn't see, like A18 on a 49F040 being tied to VCC. It still refused to run...

Doing some research on the GG and different BIOS versions, some GameGears check 0x7FF0 for a line of text, which is in fact present at the location it needs to be. I have tried everything and yet it still refuses to boot up. I am rather upset by all of this, which is why I am going to make my own flash cart for the GG! BLARG!

VileTim and others have made CPLD versions of the original 315-5912 Mapper chip included in a few Sega Master System and Sega GameGear carts. Obviously the goal is to design a board that makes it so we can use commercial and modern components rather than salvaging and destroying official devices. The first point I am trying to make is to design a board that supports 512 KByte ROMs, homebrew or otherwise. Then I would like to add SRAM and a battery because I am hopeful for a music tracker that runs on SMS and GG in the future.

LSDj is getting old in my opinion and there are other devices that make unique and varied sounds, such as the 76SN489 inside of the GG and SMS.

Anyhow, I have now completed a version with an official mapper that 'should' support up to 512 Kbytes when using a 49F040 ROM.



I am also working on two simultaneous versions that include SRAM and a battery, but they are going much slower because I am running out of room for traces...






The board containing a 49F040 still holds up to 512KBytes, but the TSOP can only hold up to 128KBytes. This downgrade is because the TSOP is much more available than the 49F040 and much easier to route traces to.

The two latter boards are also a little taller than the other board. The first one I designed was based on an actual official game, garfield or something, which does not fill the entire shell. The other boards I measured just how much more I could fit inside of the shell and still have it close without any cutting, which is important to me.

The second biggest concern of my boards is that I hope to get them to support Sega Master System Homebrew and ROMs. The jumper between cart pins 41 and 42 is an SMS/GG selector. when it is bridged, the GG runs in GG mode, but when it is cut, it runs in SMS mode. I have done no (successful) testing of this just yet, but I will surely post about it once I do.

Stay tuned