Serial Communication from BasicATOM to BS1 (prop1 board actually)

Blake

Hey there,

I know that you guys might not know the ins and outs of the ATOM chip, but I at least want to confirm my BS1 code side of things. I have a pin on my basicATOM chip connected to pin 7 of my BS1 on the prop1 board. The grounds of both boards are tied together, although they use different power supplies.

The basicATOM is always the transmitting chip, and the BS1 prop1 is always receiving. A number from 1 to 9 is the data. Only ever one number at a time, and then a carriage return to end the number for the BS1.

This setup does not function. I can debug the BS1 and see that it is ready and waiting for action, and I can debug the ATOM and see that it indeed sends out the correct number from 1 to 9. But the BS1 does not seem to be receiving the information.

I have only tied grounds together and have the one serial wire. No resistors, caps, or anything else.

ATOM code:

if lvert>200 then '(if left forward)
	if rvert>200 then '(if right forward)
		serout P2, N2400, [dec 1, CR] '(left and right forward)
	elseif rvert<80 '(if right reverse)
		serout P2, N2400, [dec 3, CR] '(left forward and right reverse)
	else '(if right stopped)
		serout P2, N2400, [dec 2, CR] '(just left forward)
	endif
elseif lvert<80 '(if left reverse)
	if rvert>200 then '(if right forward)
		serout P2, N2400, [dec 4, CR] '(left reverse and right forward)
	elseif rvert<80 '(if right reverse)
		serout P2, N2400, [dec 6, CR] '(left and right reverse)
	else '(if right stopped)
		serout P2, N2400, [dec 5, CR] '(just left reverse)
	endif
else '(if left stopped)
	if rvert>200 then '(if right forward)
		serout P2, N2400, [dec 7, CR] '(just right forward)
	elseif rvert<80 '(if right reverse)
		serout P2, N2400, [dec 9, CR] '(just right reverse)
	else '(if right stopped)
		serout P2, N2400, [dec 8, CR] '(both stopped)
	endif
endif

and my basic Stamp 1 code:

' {$STAMP BS1}
' {$PBASIC 1.0}


'P1 = relay 1, M1 forward  (left)
'P2 = relay 2, M1 reverse
'P3 = relay 3, M2 forward  (right)
'P4 = relay 4, M2 reverse

SYMBOL direction = B2

Main:

  SERIN 7, T2400, #direction

  IF direction = 1 THEN bothforward
  IF direction = 2 THEN LforwardRstop
  IF direction = 3 THEN LforwardRreverse
  IF direction = 4 THEN LreverseRforward
  IF direction = 5 THEN LreverseRstop
  IF direction = 6 THEN bothreverse
  IF direction = 7 THEN LstopRforward
  IF direction = 8 THEN bothstopped
  IF direction = 9 THEN LstopRreverse

GOTO main

bothforward:
LOW 2
LOW 4
HIGH 1
HIGH 3
GOTO main

LforwardRstop:
LOW 2
LOW 3
LOW 4
HIGH 1
GOTO main

LforwardRreverse:
LOW 2
LOW 3
HIGH 1
HIGH 4
GOTO main

LreverseRforward:
LOW 1
LOW 4
HIGH 2
HIGH 3
GOTO main

LreverseRstop:
LOW 1
LOW 3
LOW 4
HIGH 2
GOTO main

bothreverse:
LOW 1
LOW 3
HIGH 2
HIGH 4
GOTO main

LstopRforward:
LOW 1
LOW 2
LOW 4
HIGH 3
GOTO main

bothstopped:
LOW 1
LOW 2
LOW 3
LOW 4
GOTO main

LstopRreverse:
LOW 1
LOW 2
LOW 3
HIGH 4
GOTO main

N2400 for the ATOM is: normal (non-inverted) data, no parity, 8 bits, high and lows driven by stamp, 2400 baud.

T2400 for the BS1 is: true data, no parity, 8 bits, 1 stop bit, 2400 baud.

Are these the same?
Any ideas on why this setup isn't working would be awesome. Thanks.

stamptrol

I haven't used the ATOM, but have done a bit of serial communication.

Regardless of the use of the words "normal", "true", "non-inverting" or "inverting", the different manufacturers may use different (conflicting) names for the same thing.

I'd try changing one of your chips to the opposite format (inverted vs non-inverted) and trying that. I'd also go for straight ttl levels. I assume the ATOM serial is coming off a regular i/o pin.

In your description for the ATOM you say "high and lows driven by stamp" which usually relates to one device "stealing" negative signal levels from the other. That will work when a chip is connected to a PC, but not with two chips. Thats why ttl levels of 0V and 5V will give better results.

Blake

Thank you for the suggestion. I spent yesterday trying different combinations of true, inverted, open drain, driven, etc. without any luck. I also ditched the prop1 board and went straight to a BS1 chip. Still no luck receiving information from the ATOM chip.

Today I will try it with a BS2p40 which I have on hand to see if it will receive the serial information...

stamptrol

You might also attach a sketch of your connections.

What you're trying to do is not complicated, so there should be a simple explanation. See the Help files under SERIN/SEROUT for some examples.

Blake

Here is the basic circuit diagram of what's involved. The serial and GND wires are about 4 feet long right now. The 1K ohm resistor in there is something I was trying to pull up the serial line towards the end of the day yesterday. I think it may need to be a higher value or removed altogether.