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Thinking about yet another board design...

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Posted: 2012-05-29 13:26 
I hate to admit it, but I just broke down and bought a serial LCD. A little bigger (depth-wise), but easier to interface if you're limited on pins.

Alan KM6VV

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Posted: 2012-05-29 15:39 
Yep, Serial LCDs can be nice when you are low on IO Pins, But parallel is nice when you have several free pins, as that data is that you control the timing of the data, so it less susceptible to being corrupted than the serial ones are, unless of course if you have a hardware serial port available...

Still testing the new board in the remote control. Having a few issues with timing of the secondary analog inputs. Will work it out soon, but been busy with other stuff...

Kurt


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Posted: 2012-05-30 15:59 
Probably should continue this under Remote control, but I have been slowly working on making my DIY remote control to work with this new board.

So far I now have all of the inputs working :D. This includes using the inputs from the Multiplexer... Next will to be get it to work with the XBee on USart0.
Will work on making it such that maybe I can have it be programmed from the PC over the XBee. So would need to be in serial replacement mode at power up with it's DL pointing to the the XBEE that is connected up to the PC. After it gets past the bootloader it will then switch into packet mode and start talking to whichever robot you have selected. Also since in this mode, I no longer have a standard debug terminal, so may write a quick and dirty VB app (I think I started one earlier), that my program can send debug information to and potentially get debug commands from.

With my current DIY Remote control code for this board, I have it read all 6 standard Analog inputs per pass and only up to one set of 2 of the extended ones. I then setup the extended ones for the next 2 and return. This gives a little time for the Analog signals to stabilize from the new set of pins before I try to sample them...

In case anyone wishes to see the WIP...

Kurt


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File comment: WIP - Not done - Won't work Yet... :D
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Posted: 2012-06-02 12:22 
Quick update:

Having some issues with getting the XBEE to work in the DIY on USART0 with the OLED on USART1. For some reason, when I try it, the USART0 TX stream is corrupted, where the TX1 stream appears to also come out on TX0. If I don't have my jumpers in place to enable the XBEE this does not happen. Have traced some of the IO lines so far everything appears to be OK...

Next will try unplugging the OLED display... If I make Rev 003 of the board, I am now wondering if I should instead of using the resistor divider approach for voltage conversions for the XBEE, instead go to a chip like the Parrallax adapter does 74LCV244A. Could use a large 20 pin version, that should hopefully fit under the XBEE, bit taller than I would want... I sort-of remembered having issues before with the Arduino Mega shield and the XBee/OLED until I used this adapter...

Any other ideas?

Kurt


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Posted: 2012-07-17 17:02 
A R2R ladder does seem to be the easiest way and will perhaps use less space if SMD resistors are used. One could also look at Delta Sigma but that is probably equivalent to making a mountain out of a mole hill; not to mention the extra cost. I could not find any data sheet with 74LCV244A? Perhaps I am looking in the wrong place.

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Posted: 2012-10-10 07:41 
Could you design one with a smt processor ?

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Posted: 2012-10-10 09:51 
DiaLFonZo wrote:
Could you design one with a smt processor ?

Yes, could design with SMT... Most all of the other components are SMT. My only issues are my old eyes and hands are not very good at hand soldering those really small pins... Should probably someday try making a solder mask and either try toaster oven or frying pan approach...

Kurt


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Posted: 2012-10-10 10:12 
Ok i understand.
I can solder.. ;)
Did you ever try with a Heat Gun..?

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RobotShop inc.
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