Tuesday, December 25, 2012

Merry Christmas! Maligayang Pasko!!!

From the crew at Dysfunctional Technologies.
No, I'm not telling which one is me.


Since PONG was such a snap (heh) - why not do BREAK OUT for the PIC12F1840? Same hardware as the PONG game (you will have to turn the paddle sideways for left to right, instead of up to down). A lot of the infrastructure for the PONG game remains - just change the position / orientation of the paddle, change the graphics, and change the game play. Yeah, that's _all_ that needs to be done. Sure.

I've just started this today - I have the title screen changed and the paddle orientation complete. Working on the game play now. Nothing worth releasing the software yet. If you want to see what is basically in the guts of this game, go take a look at the PONG post HERE and check out the source code links.

UPDATE 12.1226:
The title screen, field, paddle and ball are done. Scoring and life counting is done. Wall collision and paddle collision detects are implemented. Loss of a life if you miss the ball is implemented. Video timings are (mostly) at spec. All I need to do now is put in the bricks!

UPDATE 12.1226:
I'm going to take the opportunity to try a new timing scheme I have been thinking about. Instead of timing the video lines throughout the code, I am going to let a TIMER0 interrupt service routine generate the video signals (except for actual data). This should be interesting.

UPDATE 12.1226:
It's possible to use the timer0 interrupt to time the video signals -  for the most part I am getting a clean signal with no jitters - but some of the tweaking is AWFUL. I think what I actually have is a hybrid between using the ISR and the manual timing. More work to be done!

UPDATE 12.1227:
Using the timer0 interrupt has been fully implemented. Everything is working as before, but now all of the nasty 'Timing Fudge' (usually a bunch of NOPs) has been removed from the code. I can change the graphics now without having to go through and tweak each of the individual lines. This is _really_ nice. And the screen is rock solid.

Friday, December 21, 2012

Chinese Meteor Lights (8 Pin Micro, 18 LEDs)

UPDATE 12.1222:
 As an experiment, I wired up their 8-pin part to a ICSP header and connected it to a PICKIT2. Well, it's not a 12F629 - in fact, the PICKIT2 reads back an ID of '0', which I think means the device isn't responding back properly. Anyone out there know what Microchip device has an ID of '0', if any?

So it's not a Microchip PIC - probably. It could be some other micro, or a specialty part as I said before. BUT, the important thing is that a PIC12F629 _can_ work in the design. And that gives me 20 individual LEDs on an 8-pin PIC with no additional hardware. And that makes me _really_ happy. Just think of the upgraded 'Iron Man Chest Arc Reactor' I can build now!

Okay, I revisited the Chinese Meteor Lights with 18 LEDs that has an 8 pin device controlling the LEDs. At first it was thought that the device was an 8-pin micro of some sort, maybe a PIC12F629. After removing their part and replacing it with a PIC12F629 and trying some programming - I deemed that the original part was not a standard 8-pin micro and probably some type of specialty part, a-la the UCS1212.

Well, a blog reader informed that yes, indeed, you should be able to do this design with an 8-pin PIC12F629. You just need to tristate the GPIO pins to the LEDs you do not want lit.

After years of working as a validation engineer on new silicon, I am not hesitant to go back and rerun tests if questions are posed. No ego here. Thank God for that. Sometimes you are right - sometimes you are wrong. And sometimes, when you are wrong, it means the situation is actually better.

So - it turns out that I did the tests I ran before _did_ tristate the unwanted GPIOs, but I was still seeing multiple LEDs being lit - albeit that only the target LED was fully bright, and the rest were semi-bright, looking quite like leakage of some sort.

It turns out that I did my testing with the PICKIT2 still connected to the design. The PICKIT2 allows you to program the PIC12F629 while assembled in the design. Nice. But the PICKIT2 connects to GPIO0, 1, & 3 and can mess things up - which I found out when I disconnected the PICKIT2 and the meteor light started behaving as expected / desired.

So - yes, it is some sort of 8-pin micro. Yes, you can replicate the design using a PIC12F629. So - have at it!

Here's a new schematic (V2.00):

Here's source code for the test program:

Meteor_Lights.ASM (V1.02): http://pastebin.com/3dVrGELs
Common.INC (V1.04): http://pastebin.com/rKDCCKZS

Videos and pictures after the break.

Wednesday, December 19, 2012

First Game Of Video Ping Pong (1969)

Documented! And now the video is on YouTube.

Sheesh. Some guys made careers of this stuff. I'm doing it in my retirement.

Friday, December 14, 2012

PONG (PIC12F1840)

UPDATE 13.0109:
That tune. It's. Stuck. In. My. Head...


A new update soon. I have a couple of bugs to squash.
UPDATE 12.1231:
I split out all of the NTSC stuff into it's own module - NTSC_Interface.INC and NTSC_Interface.ASM. Hopefully this makes for easier implementation of NTSC video in your projects. I also have ODD/EVEN fields implemented and the timings are _really_ tweaked to try to meet spec. The big LCD TV is working better (VSync locks now, data is clean, but there's a weird shifting of the line data), and everything else I have thrown at it works great, including my Sony LCD goggles.

PONG.ASM (V4.04): http://pastebin.com/Wbxbg94R
Common.INC (V1.10): http://pastebin.com/rMJcnLqt
NTSC_Interface.ASM (V1.00): http://pastebin.com/aPi9eKRJ
NTSC_Interface.INC (V1.00): http://pastebin.com/nXCannBS

Enjoy - and Happy New Year!

UPDATE 12.1229:
In order to get the large LCD TV working, I've had to implement odd/even fields to the video generation. So - long story short - there's a lot of CRAP information out there on what the video signal is supposed to look like. I'm surprised I've had anything working, with the BAD information that I have been working from.

Happy ending? I'm close to getting absolutely correct video implemented, and it's all thanks to this webpage:


Which has wonderful timing diagrams like this:

Who knew there were SIX pulses in the midst of the vertical synchronization phase for NTSC video, not FIVE as some as said. And who would have thought it would make such a difference to the video quality! One must NOT mix up the timings for PAL/SECAM and NTSC, or bad things will happen.

You're welcome. Merry Christmas.

UPDATE 12.1228:
Version 4.01 of PONG is now released. It has COMPUTER mode for player 2. Just press and hold the PLAYER 1 BUTTON while powering up. A large 'C' should be in the upper right corner of the screen.

Also note - the player 1 joystick handling has been modified for the Tandy joystick (see pics below). The original code is still in the source, just commented out.

PONG.ASM (V4.01): http://pastebin.com/ViHhnMG1
Common.INC (V1.10): http://pastebin.com/rMJcnLqt

UPDATE 12.1228:
I crammed my second PONG board into an old Tandy joystick. Well, 'crammed' isn't really true, because there's plenty of room for the board, cables and Audio/Video jacks. Now the batteries? Those may post a problem. I'm just powering it from the PICKIT3 at the moment.

Top view. Looks like a normal Tandy joystick.

The front side, with the big red button that is original to the
Tandy joystick. Cheesy.

The right side, showing the ICSP header for programming
the PIC. I use this to power the device - at least until I figure
out what I am going to do for the batteries.

An upper view where you can see the joystick,
big red button, and the A/V connectors.

A view of the inside. The bottom is on the left, the top is on
the right. In the bottom, the A/V connectors are on the lower
left. The micro board is on the upper right. The top has the
original joystick and button that came with the device.

Another view of the inside.
The top is on the left, the bottom on the right.

Close up of the micro board. 1 PIC, 6 resistors.
I need to add a capacitor.

UPDATE 12.1228:
3 items:
  1. This PONG post has surpassed the Dual Die Emulator post in the number of views. Thank you all very much. And thanks again to Hack-A-Day for the link from their website.
  2. I've built another PONG board, one that is to be battery powered and self-contained in an old Tandy joystick. And after an hour of soldering, I programmed the part and - it works! So the first one wasn't a complete fluke. This should give hope to anyone else out there who is building this project.
  3. I'm programming in a mode for making player 2 a computer player. When I finish, I'll post the code for anyone who is interested.
UPDATE 12.1227:
I've been working on BREAK OUT and there's lots of lines with fixed, single pixels and I was having a heck of a time getting everything lined up and the video signal timings correct. I was tweaking my signal timing routine and adding NOPs all over the place and spending a LOT of time getting things right that would just break when I added code or changed the graphics.

So I finally broke down and started experimenting with using a interrupt service routine to control the video signal, with the timings based on TIMER0. It turned out great, so this morning a did a major overhaul of PONG and turned over control of all of the video signal timing to a TIMER0 ISR.

Oh my, I should have done this in the first place.

All of the 'Timing Fudge' comments with the associated NOPs are gone. You won't find stray NOPs anywhere except for placing pixels on a line - no more peppering the code with NOPs to get the sync width or line width correct. It is _so_ clean and rock solid now, and so easy to change and maintain, that it almost has me in tears to think of how much time I have spending pushing 250ns slices around in the code.

Since it's a major change, PONG has been bumped up to V4.00.

PONG.ASM (V4.00): http://pastebin.com/WcR2DFfx
Common.INC (V1.10): http://pastebin.com/rMJcnLqt

UPDATE 12.1225:
I've started a new game for the PIC12F1840 - BREAK OUT. The new post is HERE if you are interested.

UPDATE 12.1224:
Ah, damn. There's always another bug.

While filming the V3.06 demo, I noticed that the ball would sometimes hit the upper sideline and not bounce off at an angle - it would just continue to follow the sideline until hit with a paddle, and then take off following the sideline to the other paddle, ad nauseum. Yeah, it bugged me, and I fixed it in my sleep last night. I was able to come into the lab this morning, go directly to the problem in the code and fix it. Nice. Weird, but nice.

Also, the _DEBUG_ option is set to FALSE, so there's no VSYNC flag pulse being generated on GPIO2.

And some timing fixes. And I added a blank and then two white lines after the Copyright, because it looks good.

PONG.ASM (V3.07): http://pastebin.com/gUpisB8L
Common.INC (V1.10): http://pastebin.com/rMJcnLqt

Enjoy! And Merry Christmas!!!

UPDATE 12.1223:
Here's a semi-short movie of what you will get if you build this project:


If you do build it, I hope it's worth it :) Seriously, if you do build this project, I would enjoy and appreciate feedback and pics of your build.

Older updates and the orignal post after the break.

Thursday, December 13, 2012

NTSC TV Interface (PIC12F1840)

UPDATE 12.1231:
As you may know, the preliminary work on video from the PIC led to creating of a PONG game. Well, that game has led to a LOT of work done on the NTSC interface. And as part of that work, I split out all of the NTSC stuff into it's own module - NTSC_Interface.INC and NTSC_Interface.ASM. Hopefully this makes for easier implementation of NTSC video in your projects. I also have ODD/EVEN fields implemented and the timings are _really_ tweaked to try to meet spec. The big LCD TV is working better (VSync locks now, data is clean, but there's a weird shifting of the line data), and everything else I have thrown at it works great, including my Sony LCD goggles.

I am including the full PONG game so you can see how the NTSC_Interface module was integrated into the game itself - and hopefully it will be a learning example so you can implement NTSC video into your own PIC project.

PONG.ASM (V4.04): http://pastebin.com/Wbxbg94R
Common.INC (V1.10): http://pastebin.com/rMJcnLqt
NTSC_Interface.ASM (V1.00): http://pastebin.com/aPi9eKRJ
NTSC_Interface.INC (V1.00): http://pastebin.com/nXCannBS

Enjoy - and Happy New Year!

UPDATE 12.1220:
Thanks to helpful readers - I know have a method to post source code.

The main program (Video_Game.ASM): http://pastebin.com/Jc5k3G0m
A common file I drop in all projects (Common.INC): http://pastebin.com/PEmji9VG

Let me know if that gives you any problems.

UPDATE 12.1214:
We have a bouncing ball! I am updating the video buffer during the vertical sync.


UPDATE 12.1213:
Data retrieval from the EEPROM is working now. It also simplifies the code quite a bit. I put a monochrome (1 bit - black or white) 32x32 picture of my son in the EEPROM and this is how it looks. Nice! Pixelicious, but nice!

Original post after the break.

Tuesday, December 11, 2012

Amplifier Interface (PIC12F1840) - Revisited

It's been a while since I worked on this project. I guess it's time to clean it up and finish it. So, here are the details:

I had an old mixer/amplifier board taken out of something that had broken (it was a Fukuda DVD/Tuner/Amplifier combo, and the power supply went kaput). It has a TM2313 mixer chip, which has an I2C interface, 3 selectable input, and 4 channel output. So, instead of letting it sit around and do nothing, I decided to make my own Mixer/Amplifier interface, using a PIC12F1840 as the microcontroller.

7 buttons
IR receiver
I2C interface
3 input selectable
Backlit LCD display

So the hardware is pretty much done - I even have a case for it, once the programming and testing is complete. More as I make progress.

Pictures after the break.

Friday, December 7, 2012

1-Wire Joystick (PIC12F1840)

UPDATE 12.1209:
Success! I have three thumbsticks (each with their own PIC12F1840) communicating over the same One-Wire interface to another PIC12F1840, which is displaying the thumbstick information on an I2C LCD.
Bus-backoff is working well, speed was dropped a bit (now only 50 reports per second per stick), and collisions are unusual. The important thing is making sure no incorrect or corrupted data is reported.

I only have three thumbsticks connected, because I didn't want to waste my precious perf board on a fourth.

I love it when things work.

UPDATE 12.1208:
Well, it's working. I need to clean up the code a bit. But - it's working! BTW: The red dongle to the top is the PICKIT3 programmer for the PIC12F1840. The umbilical going to the lower-right is the connection for my analyzer (USBee ZX). And the LCD is a 2x16 character with an I2C interface. Yes, I'm bit-banging two pins on the PIC to emulate an I2C interface. Right now, the code consumes 717 words of PIC memory, out of 4096 words. I'm going to shrink that a bit. There's an I2C interface module, a LCD interface module, the One-Wire interface module, and the small bit of main code.

 Idle - thumbstick (button) unpressed and the thumbstick centered.

 The thumbstick (button) pressed.

 Y-Axis (Up-Down) fully DOWN.

 Y-Axis (Up-Down) fully UP.

 X-Axis (Left-Right) fully LEFT.

  X-Axis (Left-Right) fully RIGHT.

Back to the idle state.

 UPDATE 12.1207:
I've been working on the code and I found a minor hardware issue - the X-Axis was reversed. So I fixed that and updated the schematic (below). Added a few notes, too.

The code is pretty much done on the transmitter side - I need to work on the receiver now. Maybe just a PIC with an attached I2C LCD to display the info. That should be entertaining.

Each report from the device contains 3 bytes - the first byte is the identifier, plus the button information. High nibble is always 'D' (B'1101'), next nibble is the device address in bits 3-2, and finally the button state information in bit 0. The next two bytes are the X-Axis and Y-Axis information. Reports are only made if a state change to the button, X-Axis or Y-Axis is detected. Reports consume 400us on the bus, and there is always 5ms between reports - to allow for other devices (up to 4 total) to get on the bus and report. That means that there will be a maximum of 200 reports per second - is that a good enough response time? I've also implemented a crude bus-backoff algorithm just in case some other device is already using the bus to report.

That's it for now - more as progress is made.


Here's a little module I whipped up. It's a PIC12F1840 interfaced to a PS1 thumbstick. It has a 1-wire interface to whatever wants to use the joystick information. There are two axis - x and y - and a pushbutton (press the thumbstick). Each module can have a unique address (2 bits), so you can have up to 4 modules on a system. The device information is encoded in the packet sent to the host.

I'm still working on the code. I am using a variant of the 40khz IR transmitter - I am going to bump up the speed - and the same work will need to be done on the 40khz IR receiver code on the host.

More as I make progress.

Wednesday, November 28, 2012

Cat Toy (PIC12F1840)

I decided to revisit the 'Cat Ball' after I found the original board in my project box. It looked like I had cannibalized the board for parts, so it was definitely not working. And the perf board was actually broken in half. Oops.

So - instead of a 'Cat Ball', we will just call it a 'Cat Toy'. It has a PIC12F1840 at the heart, a piezo speaker to play sounds / music, two LEDs (green and red) for color, and a vibrating motor I scrounged from an old cell phone.

As always, here's the schematic:

And a few pictures:

Crowded! There's a lot on this little board.

The ugly underbelly. I was more concerned with fast than pretty.

And a short movie:


Tuesday, November 27, 2012

Chinese Meteor Lights (UCS1212, 30 Multi-Color LEDs)

Another trip to Uno (a local discount store), another meteor light find. This one is a large tube with only 30 LEDs - 3 LEDs per bank vs. 4 LEDs, only 10 banks vs. 12 banks - but they are multi-colored (red, green and blue) instead of either just all white or all blue. It still uses the UCS1212 IC in the design, but done just a _little_ bit differently. And it's a little cheaper than the larger, 48 LED tube (p189 vs p219 - p30 difference which is about US$0.75). Here's the schematic:

And here's a direct link to the UCS1212 Datasheet (PDF) - be forewarned, it's in Chinese.

Saturday, November 24, 2012

17 LED Light Bar (PIC12F1840)

UPDATE 12.1127:
I updated the schematic - removed the PINK LEDs, as they are doing some weird leakage nonsense. So they are replaced with another two RED LEDs. I also changed the way that the POWER LED is handled. And I updated the amplifier circuit for use with a 1" speaker instead of an actual microphone.

Another project I just wanted to put up in a post before it gets lost. It's a 17 LED Light Bar, approximately 81cm long, meant to be mounted about the Flat Panel TV set. It does patterns like the other LED projects I do, but also a 'Music Mode' so it acts like a colorful 'equalizer' bar. I am building it for my father-in-law for Christmas, so he can have some 'bling' when doing Karaoke.

Still working on the microphone preamp circuit. I'm a software guy who also knows digital hardware, but this analog stuff will be the death of me yet.

Front side - 81cm long, 17 LEDs

Back side - holes cut in the back to make room for the larger components (caps).

Close view of all of the good stuff sticking out of the back.

Tuesday, November 20, 2012

Iron Man Chest Arc Reactor (PIC12F1840) V3.00

I decided to rework the Iron Man Chest Arc Reactor - it is now at version 3.0. I reworked the old hardware for the 2N4403/2N4401 transistor scheme, which gives me 8 individually controlled LEDs instead of 4. So instead of 4 groups of 4 LEDs, there is now 2 groups of 8 LEDs.

Ugly backside of the board before the rework.

Ugly frontside of the board before rework.
Too many components, especially 1K ohm resistors.

Removing the old wiring.

Wiring removed, now removing the extra components.

All components removed, except the PIC, ICSP header and the LEDs.

Rewiring the LEDs. MUCH nicer.

Rewiring the ISP header.
I have wired up so many of these, I could do it in my sleep.

The finished new version 3.0 Chest Arc Reactor.

Short demo movie below the fold...