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SAA3008 IR emitter problems ...

  • Thread starter Henrik Koksby Hansen
  • Start date
H

Henrik Koksby Hansen

Jan 1, 1970
0
Hi.

Anyone who has experience with the mentioned IC ? ...


INTERFACING

I've made the circuit always transmit the same code, by shorting DRV0N
to SEN0N.

DRV6N has no connection, so that it operates in mode1.

DRV0N-DRV5N is connected to ADRM through a dip-switch,
so that it is possible to change the address.

There is at no time connected more than one driver-channel (DRVXN) to
ADRM..


PROBLEM

When the circuit is switched on, it some times enters a, to me,
unknown state, where it transmits 12 bit instead of the wanted 11 ...
The problem only occurs from power up, and is only solved by cutting
the supply and discharging the circuit.

I have tried both with and without 10k pull-up resistors on the
driverchannels, but it makes no difference.


MEASUREMENTS

Here are the measured pulse sequences, in the sequence:
correct A, wierd A, correct B, wierd B, correct C ... osv. osv.
(reference and toggle is not listed). It is listed which driverchannel
is connected to ADRM.

N/C 111 000000
N/C not seen in the "wierd" condition at any time.

drv0 000 000000
drv0 001 1000000

drv1 001 000000
drv1 101 1000000

drv2 010 000000
drv2 001 1000000

drv3 011 000000
drv3 101 1000000

drv4 100 000000
drv4 011 1000000

drv5 101 000000
drv5 111 1000000


I hope that anyone has a solution or a good idea to what is wrong. :)


Regards,

Henrik Koksby Hansen
 
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