Help on Propeller PCB
Discovery
Posts: 606
It has taken awhile but I have finally succeeded in checkout of the major code in operating my commercial plasma cutting X, Y, Z machine using the Propeller Activity Board. The COGs work properly and all X, Y, and Z drive mechanisms work perfectly. In order to continue with the development project I must move to the commercial PCB stage. I purchased the P8X32A-D40 DIP Propeller, the 24LC 256 EEPROM chip, the 5 MHz crystal, and the LM 2937ET 3.3 volt regulator.
I plan to place the hardware on a double sided PCB...do you have guidelines on circuit trace layout, by-pass caps, etc. Is there anything different between the surface mount propeller and the DIP propeller that I need to take into consideration?
Should the USB interface be made with individual components or use the ready-made board?
Is the four channel 12-bit SPI ADC DIP #604-00061 the same as the surface mount ADC on the Activity Board.?
I want the commercial PCB to operate just like the activity board...clock speeds everything. Do you see any problems in doing that?
Is it possible to download X and Y coordinates (in floating point format) to Propeller memory or other memory so that the Propeller can access each pair and thus drive the X-axis and Y-axis mechanisms?
Sincerely,
Discovery
I plan to place the hardware on a double sided PCB...do you have guidelines on circuit trace layout, by-pass caps, etc. Is there anything different between the surface mount propeller and the DIP propeller that I need to take into consideration?
Should the USB interface be made with individual components or use the ready-made board?
Is the four channel 12-bit SPI ADC DIP #604-00061 the same as the surface mount ADC on the Activity Board.?
I want the commercial PCB to operate just like the activity board...clock speeds everything. Do you see any problems in doing that?
Is it possible to download X and Y coordinates (in floating point format) to Propeller memory or other memory so that the Propeller can access each pair and thus drive the X-axis and Y-axis mechanisms?
Sincerely,
Discovery
Comments
You may have to wait a while before someone can reply. You have a lot of questions.
You'll want bypass caps next to each set of power pins on the Propeller. There's a recent thread by greybeard about a board he's making. There are a bunch of suggestions made there.
If you have room for the DIP, then IMO, it's a good choice. The DIP package seems to be better behaved than the surface mount ones (at least when over clocking).
It depends. I prefer to keep the board simple and use ready made USB to serial devices. I like these $2.20 boards from ElectroDragon. This particular board needs to have the DTR line connected to the Prop's reset line through a capacitor. I add the capacitor to my PCB design and include a place for a jumper in case I want to use a PropPlug instead of the $2.20 board.
No it's not. There's a BOM for the AB which lists the part number. The chip is available at Digi-Key.
Yes it is possible. There shouldn't be a problem as long as you're using code to handle the floating point encoded data.
Would you help me out with the ADC what is the BOM and the AB? I will order it from Digi Key as soon as I know what to order.
Is there some code that shows how to make this function work. I define the X and Y data as floating point variables but how do I direct the file to memory?
Sincerely,
Discovery
Publison found the Digi-Key part # not long ago. I think it's this part.
I'd think the easiest way would be to use a SD card but it's also possible to have the Propeller interface with the PC and use a program on the PC to send data to the Propeller.
I don't know how to do either of these with C on the Propeller.