In SX Microcontrollers, SX/B Compiler and SX-Key Tool, sirnfs wrote:

Hello,
 

I am trying to communicate with a CMOS image sensor via I2C.  The image sensor uses a serial format called SCCB, which is identical to I2C as far as I can tell.  The SCCB data sheet can be found here:  [url=http://www.ovt.com/pdfs/ds_note.pdf]http://www.ovt.com/pdfs/ds_note.pdf[/url] 

 

I am using the SX52 as well as SX/B.  I have attempted to troubleshoot the code with the Debugger using the SX Key oscillator, but I am not even sure that this is possible (timing issues?).  The code is shown below.  Note:  (2) 4.7 kohm pull-up resistors are being used on the SDA pin (RE.0) and SCL pin (RE.1).  I have also noticed what seems to be some sort of contention.  When I attempt to enter Debug mode, the programming process will freeze.  To get rid of this problem, i power-down the SX52 and then reapply power.  I realize that there it is not possible to test this code, but I would appreciate if anyone could take a look at the code or possibly comment on a solution.  

 

Thanks,

 

Mike  

 

' -------------------------------------------------------------------------
' Device Settings
' -------------------------------------------------------------------------
DEVICE SX52, OSCHS3
IRC_CAL IRC_SLOW
FREQ 5000000
PROGRAM start_point
' -------------------------------------------------------------------------
' Variables
' -------------------------------------------------------------------------
Ack CON 0
Nak CON 1
SDA CON "RE.0"
Recv VAR bit
tmp VAR byte
tmp2 VAR byte
sndcode CON $C0
regnum CON $1C
sndcode2 CON $C1
' -------------------------------------------------------------------------
' Program Code
' -------------------------------------------------------------------------
start_point:
I2CSTART SDA            ' start transmission
I2CSEND SDA, sndcode ' send id address
I2CSEND SDA, regnum, Recv ' send sub-address
I2CSTART SDA  ' restart new transmission
I2CSEND SDA, sndcode ' send id address again
I2CRECV SDA, tmp2, Nak  ' receive data from slave
I2CSTOP SDA  ' stop transmission
__RAM($1F) = tmp2 ' store received data to RAM

BREAK
SLEEP

---------- End of Message ----------


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