i2c interface with LED driver PCA9532

[Dave]

I notice the led's are drawn backwards.... It will be kind of tough to get them to light....

[koodiifin]

Lol, that's what happens when I draw a schematic in a hurry. Thanks for noticing. The leds are wired correctly on my breadboard though. I just can't get any response from the PCA9532. I've scoped the SDA and SCL pins and I can see the correct clock signal on SCL and various "data" on SDA, so I know that the PIC is outputting something. When I add the optional label argument to the i2cwrite function, the program constantly jumps to the label. Which means that I'm not receiving an acknowledge from the device. I've also tried adding "DEFINE I2C_SLOW 1" to my program because I'm running a 20MHz clock, but it did not help.

[koodiifin]

Here is my new code and a shot of my oscilloscope to show the output. I can see that I'm not getting an acknowledge, but I do not know why.

'****************************************************************
'*  Name    : i2c comms test with led driver                    *
'*  Author  : Cody Finden                                       *
'*  Version : 1.0                                               *
'*  Notes   : SOFTWARE FOR A 16F887 TO WRITE TO A LED DRIVER    *
'*          : OVER THE I2C PROTOCOL                             *
'****************************************************************


#config
 __CONFIG _CONFIG1, _HS_OSC & _WDT_ON & _PWRTE_ON & _MCLRE_OFF & _CPD_OFF & _BOR_ON & _IESO_ON & _FCMEN_ON & _LVP_OFF 
 __CONFIG _CONFIG2, _BOR40V & _WRT_OFF 
#endconfig


DEFINE OSC 20


ANSEL =     %00000000
ANSELH =    %00000000
TRISA =     %00000000
TRISB =     %00000000
TRISC =     %00000000
TRISD =     %00000000


SDA         VAR PORTD.3
SCL         VAR PORTD.2
led         var portc.5
addr        var byte


INIT:
PAUSE 400   'let hardware settle


'PCA9532 i2c address(7 bits + 1 bit for R/W) 
'Slave address is 1100(A2)(A1)(A0) + (R/W)
'In my setup A2 is pulled low, A1 pulled high, A0 pulled low
addr = %11000100  


MAIN:
    
'    I2CWRITE SDA,SCL,ADDR,[$12,$97,$80,$00,$40,$55,$FA,$00,$00]


    I2CWRITE SDA,SCL,ADDR,$06,[$00]  'turn off led 0-3
    led = 1     'blink led for feedback
    PAUSE 250
    
    I2CWRITE SDA,SCL,ADDR,$06,[$55]  'turn on led 0-3 
    led = 0
    pause 250


goto main