BYO Prop Plug

dgabler · 2007-05-21 22:24

Is it possible to just wire up a rs232 plug to a header pin for a prop plug for programming?
e.g.

RS232 - > Prop Chip
5 (gnd) -> 9 & 10
3 (txd) -> 31 (rxd)
2 (rxd) - > 30 (txd)
1 (cd) -> 11 (resn)

I searched but was not able to find any topic about building your own programming programmer.

Paul Baker · 2007-05-21 22:30

The information is in the Datasheet under Alternative Serial Port Connection (and the second image of the Diagrams, Schematics and Images page). Do not connect your serial port directly to your Propeller, the 12V of the serial line will damage the Propeller.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

dgabler · 2007-05-21 22:53

Missed that document. Thank you.

parts-man73 · 2007-05-22 04:52

I actually had a schematic drawn up and a circuit board fabricated for a "Serial PropPlug" I used a MAX3232 and all related components, and powered it by drawing the power for the circuit from the serial port's RTS line. I used a LDO TO-92 package 3.3v regulator. It actually worked quite well.

One small problem with my design however. The edge of the board that had the 4 pin connector that would plug into a Protoboard overlapped the power connector on the protoboard. So it was in the way of the power plug or vice versa. After realizing my mistake, the project kinda died.

I was doing it just to prove that it could be done anyway, once I saw that it worked I was satisfied. All of my computers have USB ports and I own 2 PropPlugs, so it was a pointless experiment. Probably wouldn't work on all computers, as there are many different types of RS-232 drivers used over the years.

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Brian Meade

"They who dream by day are cognizant of many things which escape those who dream only by night" - Edgar Poe

Sawmiller · 2007-05-22 18:49

http://forums.parallax.com/showthread.php?p=585009
maybe this is what your lookin for ?
·

Paul Baker · 2007-05-22 18:58

Please don't use that schematic, while it looks similar to the current one it is actually 3-4 revisions old. There were issues with that circuit which required modifications.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Oldbitcollector (Jeff) · 2007-05-22 19:10

PartsMan,

Would you mind sharing your design? I've got a friend who would like to get started in prop experimenting as cheaply as possible, and I have several MAX233's in my parts box. I'm thinking that a simple cutting of the pref-board (little shaping) should solve the issues with the connectors.

Oldbitcollector

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The comments and code above are proof that a million monkeys with a million propeller chips *could* write Shakespeare!

Sawmiller · 2007-05-23 03:23

hmmm , newzed cut me a board using a schematic like that,without the 232 chip just some resistors and transistors, and i hooked it up to a homebrew
board and programmed with it.. worked ok, i've still got a expresspcb file on it somewheres
dan
might not work with the newer protoboard thou, mine was off a stripboard
dan

Post Edited (Sawmiller) : 5/23/2007 3:36:23 AM GMT

parts-man73 · 2007-05-24 03:07

Attached is the schematic of my SerialPropPlug, I noted that you said you had "MAX233" in your toolbox. This design calls for a "MAX3232" I think you may have mistyped. Also, the MAX232 is not compatible with 3.3 volts, a MAX3232 must be used.

If breadboarding this circuit, omit the regulator portion of the circuit, in other words, everything connected to pin 7 of the serial port.

The VCC and GND connections on the IC are not show in this diagram. Be sure to connect pin 15 of the MAX3232 to GND and pin 16 to 3.3V

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Brian Meade

"They who dream by day are cognizant of many things which escape those who dream only by night" - Edgar Poe

BYO Prop Plug

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