One sweet ADC, National Semiconductor ADC08100

I spent this weekend playing with a few analog to digital convertors I have been meaning to try out, one of which is the National Semiconductor ADC08100. The ADC08100 is an 8 bit 100Msps ADC with very low power operation. To test it out I have it clocked from a PIC18F4520 running at 40Mhz and has the output being displayed on a pair of HP hexadecimal displays. Input is coming from a small Murata pot whose voltage can be adjusted over the set range of 0V to +3V.

I plan on using these ADCs for everything from video capture in basic machine vision systems to any type of ADC that needs high speed accurate conversion that can offload the ADC operation from the microcontroller itself.

TCM8230MD Camera Images Within Reach

Last night I was able issue a start command over I2c to the TCM8230MD camera module to have it start sending images. I'm now receiving valid YUV 422 data off of the 8 bit bus along with the necessary clock and sync pulses.



This camera is definitely not the easiest thing to work with. The datasheet is not as clear I would have liked and the timings necessary for the startup sequence took a little bit longer to figure out than I had expected.


The next step will be to be to send the camera a few more control codes to lower the frame rate and resolution to get the data rate to a more manageable level for the pic. I'm hoping to capture and display my first usable image over the weekend.

Custom PCB for Toshiba TCM8230MD Camera

I recently purchased a few small TCM8230MD CMOS cameras made by Toshiba from SparkFun. I plan on using the camera for some machine vision experiments as they are controlled by an I2c bus and have an 8 bit parallel video out with sync and clock. This makes them very microcontroller interfacing friendly. I plan to use a higher end PIC micro to receive the picture data and process the received video frames. The only issue is that I didn't realize how small these cameras actually are until I tried to use one.

My first attempt at soldering didn't go so well as the solder pads on this device are extremely small. Since no breakout board is available and the lead spacing on this device appears to be non-standard, I went for a custom PCB design.

I made the initial pattern in Eagle using the dimensions from the datasheet to space the solder pads for it, than drew simple traces to solder pads for two headers. I then used the instructions here to transfer the trace layout to a copper PCB.


A nice thing about this simple board is that I didn't have to worry abut mirroring the layout when printing as the orientation of the camera doesn't matter. Once the board was etched in Ferric Chloride, it looked like this:


Not bad for a quick design, there was one weak trace that was etched too much but a little solder will fix that. One note about etching, It took much longer to etch than anticipated. About 20 minutes was needed with me agitating the board for the last 10 minutes.

A reflow procedure was used to solder the camera down, I did it with an electric skillet. After reflow, a quick test showed no shorts and inspection of the pins to pads looks good. I plan on starting to use it tonight.

Now that I have made the board, I would have changed a few things. I should have made pin 1 on the camera line up with the standard pin 1 location on the board. I should have also made all the header pins along one side of the board instead of two so I could use right angle headers to mount the camera vertically. I also didn't forget to drill the holes in the board for the headers, I purchased new PCB drill bits online and they have not arrived yet. I'll just solder jumpers to the pads for now. Yes i'm impatient.