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Topics - MichaelZ

Project development, ideas, and suggestions / Eagle Tips and Tricks
I have been frustrated by the Eagle Help file and spend a fair bit of time Googling for answers to Eagle issues.  So what I want to put together a list of questions and answers to [s:]"the meaning of life"[/s:] Eagle CAD.

Post here your questions, no matter how simple they seem.  If you find answers or tricks/tips post them.  Keep it simple and short. 

The information will be posted on the Wiki.
Breakout boards / Alternate Ethernet MAC/PHY IC's
There are the Microchip set of IC's ENC424J600 etc. but with issues of the software licensing.  Microchip

Wiznet has a series of chips but I dont know about the software. TCP/IP Chip. Attached is an article on using the W5100 with the PIC18F. 

Any others to look at?
CPLD programmable logic / PyroElectro-Create NTSC Video Output With VHDL
While poking around the PyroElectro website I ran across one of their tutorials Create NTSC Video Output With VHDL.  I took the source "ntsc_TOP.vhd" and dropped it into a CoolRunner project.  I was able to get it to compile with the XC2C256-6-VQ100 device.  Anything smaller did not have enough resources.  The original project was done with a Virtex FPGA.  I did not do anything to the original vhd file which is one of the nice features of VHDL.  All I had to do is create a new project, select the device and add the ntsc_TOP source to the project.  Simple!  Obviously the pinout changes.

I have attached a zip of the ntsc_TOP.vhd and NTSC.xise files.


Project logs / Chinwah Projects
A couple of things I am working on. First up is the USB Toaster Oven Controller.  First rev of the PCB had silkscreen issues.  PCB size is 50mm x 50mm.

Just got these boards in.  Top is a 128x64 Graphics LCD Backpack.  PCB size is 73mm x42mm and attaches to the back of the Topway LM12864M.  It uses a PIC18F4550/4553 with 8 analog/digital, 6 digital I/O brought out to two connectors.  There is a daughter card for the Backpack with prototype area coming.

Middle is USB K Thermocouple Adapter. Bottom is USB PH Adapter.  Both are 30mm x 49mm and fit in the Serpac C-4 enclosure which is 55mm x 35mm x 15mm.

Here is a picture of the USB K Thermocouple Adapter in the Serpac C-4 enclosure.  The USB PH Adapter is the same size.

DSO Wing / 1GHz 12 bit ADC
Texas Instruments has announced a new 1GHz 12 bit ADC. ADS5400

Cheap at twice the price...$9500 USD each @100 piece quantity.  I dont think they are giving away samples... How is that Virtex-7 HT board coming?

DSO Wing / Alternate design
I have been thinking about this quite a bit.  Too much probably.  Follow this train of thought. 

  • The ADC is limited to 1v or 2v peak to peak but tolerant from 0 to 5v input. We set it to 1v peak to peak.
  • The opamp is tolerant from 0 to 5v input.
  • The DG449 is tolerant from -v to +v
  • The DG449's -v=-5v and the +v=+5v.

See attached PDF

This will allow an input to the DG449 to be 10v peak to peak.  If we have a 10:1 voltage divider between the DG449 and the opamp the peak to peak at the opamp would be 1v.  By using a scope probe with x10 and x1 you have a peak to peak input to the probe of 100v p-p and 10v p-p respectively.  We would use the OLS's 5v supply and generate a -5v on the wing using a charge pump like the LT1054. 

The two ranges would be set with the probe.  Assuming 10 divisions on the scope plot then each division would be 1v/div for x1 probe and 10v/div for the x10 probe.  To set the ground reference you ground the tip or like on my scope probes there is a switch for X1,X10,REF.

This would cut the cost dramatically and you would still have ac/dc coupling. 

DSO Wing / DSO ADG5436 replacement
I already have the ADS831's and OPA2691's.  When I get the ADG5436's I will proto the circuit and test it with the OLS.
Project development, ideas, and suggestions / PIC + FPGA based 1/4 HD color display
This is a carryover from the USB LCD Backpack.  I have a design for a PIC + FPGA based 1/4 HD color display. 

   Color LCD TFT 4.3" 480x272 with touch
   FPGA XC3S500E-4PQG208C (could use Xilinx Coolrunner)
   SRAM 512K x 24 

The PIC manages the USB interface and touch.  It creates the graphics.  The Xilinx FPGA manages the SRAM for the display and display timing.  The PIC connects to the FPGA through the PIC PMP interface.

There are enough I/O on the FPGA to add 3 or 4 ADC chips and there is enough block ram in the FPGA to make a pretty powerful oscilloscope.  The original design had three 80 MHz 8 bit ADC's but they could be wider and faster.
Tthe FPGA has enough resources to decode HDMI for a compact 1/4 HD monitor. Which ties into my interest in the EDID and the DVI connectors.

The USB can be either host or slave to support PC or peripheral interface.  We could add CF support.

There is enough RAM (512k x 24) for four video pages of 480x272 or two video pages of 640 x 360.  You need at least two pages of video RAM to ping pong the display.

It is along the path that Dangerous Prototypes and Gadget Factory have been following with the OB Logic Sniffer.  It adds RAM and the display to the previous work.

A lot of the design for the FPGA for the display and HDMI can be found in Xilinx application notes.  Microchip has the USB and Graphics libraries.

Project development, ideas, and suggestions / Advanced USB LCD Backpack
There have been a lot discussion in the USB LCD Backpack thread about advanced features.  My suggestion is as follows:

  USB host or slave interface
  CF interface
  Universal LCD support (character and graphics)
  USB power or wall wart
  Shark mount with laser interface (ok maybe not)

Hardware :
  PIC24FJ256G106 (PIC24FJ256G108)

  Microchip USB library (until DP gets its own)
  Microchip Graphics library
  Custom library pack to support LCD's  (added to my the community)
  LCD Smartie support? 


Project development, ideas, and suggestions / Smart phone remote control
I have a Blackberry and I have been wanting to use it for remote control.  It has Bluetooth and a USB port.  Experimenting with it I can of course connect to my laptop using either the Bluetooth or USB cable.  I have tried with limited success connecting to a BlueSMiRF module from Sparkfun.  Since I can connect both to my laptop, it has to do with the software in the Blackberry.  The software on a Blackberry are JAVA and the tools are available from Blackberry.  Famous last words but "it is only just software."

I have my laptop talking to the BlueSMiRF module and sending commands to a PIC18F2553 which is controlling my model train.  I would like to do that using my Blackberry.

Another project would be to use the PIC24FJ to a USB Bluetooth "dongle" on the receiver end.  I started looking into this with little success.  I bought a couple of the dongles and while they sort of work with my PC they are not recognized by the PIC host software.  They are recognized by the FTDI Vinculum but I havent decyphered what it is telling me. 

The Blackberry USB is also interesting.  It cannot host but using a PIC24FJ256 series part it should be possible to communicate with it.  From the PIC all kinds of things are possible.  "it is only just software." JAVA in the Blackberry and C in the PIC.  The both the PIC and FTDI Vinculum recognize the Blackberry as a mass storage device.  I imagine it is just what the Blackberry tells it rather than be hardcoded.  Again with the software. 

A USB master on the Blackberry would be useful.  I originally looked at the Vinculum with one host port talking to the Blackberry and the other host talking to any peripheral.  The Vinculum already understand most of the peripherals like printers and HID.  What about the Bus Pirate or OBLogic Sniffer.  I have a USB scope probe that would be nice to talk to.  The GUI for the OBLS is JAVA.  The Vinculum is not the most friendly part.  I have both the VDrive2 and the development kit.  The VDrive2 is interesting in that it has a snap in housing and SPI/serial interfaces.

Any phone with Bluetooth and/or USB should be useable for remote control.  I am sure someone sells something like that out there but I am sure it is overpriced.

Project development, ideas, and suggestions / USB sensors
With all of the experimenting with the FT232R and SPI interface, I have a couple of projects that I have built, programmed and tested.

1.  USB Thermocouple :  Simple thermocouple interface measurement from 0-1024°c using the FT232R and MAX6675.  Prototype built, software written and tested

2.  USB Altimeter :  FT232R and SCP1000 to measure absolute pressure and thereby altitude.  Prototype built, software written and tested

3.  USB PH : FT232R and ADS7835E to measure PH from 0-14.  This one is still in the testing phase.  I had to go out and buy a PH probe.

All of these were designed to be a USB dongle.  ie small. 

Schematics attached.

Any interest?  They are far enough along for a quick build and put some change in the money bucket. 

Project development, ideas, and suggestions / USB LCD BACKPACK
I have been experimenting with the FT232R as a USB to SPI interface.  Some of it is on the web at

After looking at the BP LCD interface I got to thinking that driving the LCD directly with FT232R is a bad idea and that using the '595 simplifies the software immensely.  And so it follows that it would be possible to build a backpack for a LCD to run off of the USB bus.  Sort of like the Olimex PIC-MT-USB but without the PIC.  Should be a lot cheaper.

First pass at the schematic is attached.  The original was done in OrCAD so I made it into a pdf for the time being.