Word Variable and I2C

[Scampy]

Henrik, thanks again for the reply.

Using the code in my last post (#5) the LED on channel 1 of the PCA chip fades up, all the way until pcaPwmValue reached 4096. At 4097 it went off, and as it increased (now at 6745) the LED on channel 1 has lit up but not on full brightness. What I can't understand is I have a B_MAX variable which has a value of 4095, with an "If B_PWM=B_MAX then doe something else statement which seems to be ignored. I was reading up on the variable statement and the manual comments that there is a size statement, with the use of additional modifiers, but I couldn't find any decent examples. Is there a way of simply limiting the word to 4095 something like B_PWM VAR Word size 4095 ??

[HenrikOlsson]

Hi,

Is there a way of simply limiting the word to 4095 something like B_PWM VAR Word size 4095 ??

Two ways that I can Think of right now, your way which you've somehow implemented wrong and the way I tried to explain in my previous post.

IF pcaPwmValue >= 4095 THEN pcaPwmValue = 4095   ' Clamp value at 4095
LCDOUT $FE,$D4+0,"PWM ",dec pcaPwmValue

Or....

pcaPwmValue = (B_PWM & 4095)    ' Roll over value at 4095
LCDOUT $FE,$D4+0,"PWM ",dec pcaPwmValue

By your explaination it sounds as if the PCA chip is basically doing what the second approach above does, ie start over at 4096 and again at 8192 and again 12288 and so on.

/Henrik.