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Chopperp

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Joined: 03/01/2018
Location: Australia
Posts: 1097

Posted: 11:56pm 25 Jun 2020

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HI

Just experimenting with talking between 2 uMites using I2C according to the instructions & codes in the 5.04 manual.

The two units do talk to each other but the Slave won't receive the full message from the Master.

I get the following messages:

[9] I2C SLAVE READ 3, MSG(), RECVD
ERROR: Cannot find RECVD

I take this to mean that the Slave is not receiving the instructions.
I did a fair bit of stuffing around but not getting anywhere.

I'm just trying to turn on a LED on PIN 16 on the Slave.

Any help would be appreciated.

SSETPIN 16, 8 'pin 16 & Digital Out
SPIN 16, 1
PAUSE 300
SPIN 16, 0

SUB SSETPIN 'pinnbr, cfg
I2C OPEN 100, 1000,pu
I2C WRITE &H26, 0, 3, 1, pinnbr, cfg
IF MM.I2C THEN ERROR "Slave did not respond"
I2C CLOSE
END SUB

' set the output of an I/O pin on the slave
SUB SPIN pinnbr, dat
I2C OPEN 100, 1000,pu
I2C WRITE &H26, 0, 3, 2, pinnbr, dat
IF MM.I2C THEN ERROR "Slave did not respond"
I2C CLOSE
END SUB

SLAVE

OPTION AUTORUN ON
DIM msg(2) ' array used to hold the message
I2C SLAVE OPEN &H26, 0, 0, WriteD, ReadD ' slave's address is 26 (hex)
DO ' the program loops forever
WATCHDOG 1000 ' this will recover from errors
LOOP

SUB ReadD ' received a message
print "Received Message"
I2C SLAVE READ 3, msg(), recvd ' get the message into the array
IF msg(0) = 1 THEN ' command = 1
SETPIN msg(1), msg(2) ' configure the I/O pin
ELSEIF msg(0) = 2 THEN ' command = 2
PIN(msg(1)) = msg(2) ' set the I/O pin's output
ELSE ' the command must be 3
s$ = str$(pin(msg(1))) + Space$(12) ' get the input on the I/O pin
END SUB ' return from the interrupt

SUB WriteD ' request from the master
I2C SLAVE WRITE 12, s$ ' send the last measurement
END SUB ' return from the interrupt

BTW, just found out recently that you can paste more than one line at a time into MMChat using the Paste Icon.
Very handy more running multiple lines of straight code

Brian

ChopperP

TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 12:18am 26 Jun 2020

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recvd is a variable that is used to hold the number of bytes actually received.
Try declaring it as a local at the start of the SUB.

Jim

VK7JH
MMedit

Chopperp

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Joined: 03/01/2018
Location: Australia
Posts: 1097

Posted: 12:32am 26 Jun 2020

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Thanks Jim.

Much better. LED flashes.
Had to be something simple

Brian

ChopperP

Chopperp

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Joined: 03/01/2018
Location: Australia
Posts: 1097

Posted: 12:32am 26 Jun 2020

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double post.
Edited 2020-06-26 10:33 by Chopperp

ChopperP

robert.rozee
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Joined: 31/12/2012
Location: New Zealand
Posts: 2442

Posted: 01:25am 26 Jun 2020

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shouldn't RECVD be created automatically, unless OPTION EXPLICIT has been declared earlier on in the code?

this looks like a bug in MMbasic to me, but i could be wrong.

cheers,
rob :-)

Chopperp

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Joined: 03/01/2018
Location: Australia
Posts: 1097

Posted: 03:01am 26 Jun 2020

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I wouldn't have thought that the variable needed declaring in this case.
I assumed that the demo programs were tried & tested.
Of course, I would have declared it in a real program & used OPTION EXPLICIT

BTW I forgot to remove the comment in the following line before posting. Was playing.

SUB SSETPIN 'pinnbr, cfg

Brian

ChopperP

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