Comment on my DIY protoboard

J

Jakob2803

Senior Member
I don't have the money for a Picaxe protoboard so I soldered this together myself. It has room for an 08M2+ and 18M2. They share the download socket. It is missing the switch by the battery connectors, so you cannot yet individually turn off/on each Pic.
P1110122 (Small).JPG P1110131 (Small).JPG
The goal was to use it with a breadboard, so it has those female headers on each side, for connecting jumper wires. The screw terminals on the buttom are connected to their jumpers in case you need to connected something that cannot sit on a breadboard. The upper terminals are for the power in case you want the Pics to run off something other than a battery pack.
It programs both kinds of Pic fine, as long as only one is in the socket. I hope the power switch will solve this. The 08M2+ is not connected to power yet so I connect a jumper from the larger chip to the smaller one's power header.
How about instead of powering on the one to program, I do something with turning on/off the 0v connection to the download socket?

I was wondering how you could make both pics send some data through the same socket to the terminal in the PE. I was thinking of doing something with connecting them together and having one chip tell the other when to send:
Code: 
backoff:
random w2
let w1 = w2 // 500
pause w1

main:
let dirsB =%11111101
if pinB.1 = 1 then main
if pinB.1 = 0 then send

send:
let pinsB =%00000001
sertxd ("Data =  ", #w0,13,10)
pause 100
let pinsB =%00000000
goto main
The back off part is so they do not start sending at exactly the same time. The pins B.1 and B.0 would be connected together from one Pic to the other,so they can tell eachother whether to send or not.

EDIT: I got the 16-seg LED chaser to work and I will post a video soon.
 
G

Goeytex

Senior Member
Your solder work is very good.

I don't see any decoupling capacitors for the Picaxe's or a filter cap on the supply input.

Perhaps you could post a schematic for review?
 
J

Jakob2803

Senior Member
Goeytex said:
Your solder work is very good.

I don't see any decoupling capacitors for the Picaxe's or a filter cap on the supply input.

Perhaps you could post a schematic for review?
Click to expand...
Thanks. And no there is no cap, I just manually hold one on the power terminals if there are problems.
Here is the circuit, but the power switch is missing. :)
circuit.jpg
 
N

nick12ab

Senior Member
Jakob2803 said:
Thanks. And no there is no cap, I just manually hold one on the power terminals if there are problems.
Click to expand...
It should be there all the time. Just think of all the times in the future you will have to manually hold it there and how quick it would be to solder it in place right now.
 
J

Jakob2803

Senior Member
nick12ab said:
It should be there all the time. Just think of all the times in the future you will have to manually hold it there and how quick it would be to solder it in place right now.
Click to expand...
Yeah. I am considering this a beta test. When the switch arrives I might make a version 1.0 board ;) There are still things to work out, like the shared download socket. I can not get the terminal to work with both chips transmitting.
 
G

Goeytex

Senior Member
I can not get the terminal to work with both chips transmitting.
Click to expand...
Of course not. The serout pins of the two Picaxe chips are tied directly together, meaning that when there is a high on the serout pin of one Picaxe, and a low on the serout of the other that there is in effect a direct short to ground, killing the signal and potentially damaging the Picaxe Chips.

For this kind of setup to work you need to:

1. "OR" the serout outputs, either with discrete logic or with a "Diode OR". And....
2. Code must prevent the the Picaxe chips from sending sertxd data simultaneously.

Attached is a schematic that shows one way that it might be done. I used a diode "OR" for the serouts.

A jumper is placed on either JP1 or JP2 to select the Picaxe to program.
 

Attachments

J

Jakob2803

Senior Member
Goeytex said:
Of course not. The serout pins of the two Picaxe chips are tied directly together, meaning that when there is a high on the serout pin of one Picaxe, and a low on the serout of the other that there is in effect a direct short to ground, killing the signal and potentially damaging the Picaxe Chips.

For this kind of setup to work you need to:

1. "OR" the serout outputs, either with discrete logic or with a "Diode OR". And....
2. Code must prevent the the Picaxe chips from sending sertxd data simultaneously.

Attached is a schematic that shows one way that it might be done. I used a diode "OR" for the serouts.

A jumper is placed on either JP1 or JP2 to select the Picaxe to program.
Click to expand...
Thank you. I think I already posted some code, but it does not work. :)
 
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