16F88: Inable to read pin

i2c2k · Guest

hi!

I've got a problem with my PIC16F88 application: independent of what is going on, I always get a 1 when I read the PIN_A4 with input(PIN_A4).
I used following code:

i2c2k · Guest

By the way I use the compiler version 3.150

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

In vs. 3.150, the setup_comparator() and setup_vref() functions don't
work properly for the 16F88. The comparators are being turned on
by the CCS code, when they should be turned off. This is what's causing
your problem.

To fix this problem, you need to comment out the calls to those functions,
and put in code to set the comparator and vref registers directly.
You need to make the following changes to your program, as shown in
bold below:

#byte CMCON = 0x9C
#byte CVRCON = 0x9D

void main()
{
OSCCON = 0b01101010;

port_b_pullups(TRUE);
setup_adc_ports(ADC_OFF|VSS_VDD);
setup_adc(ADC_OFF);
setup_spi(FALSE);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);

// setup_comparator(NC_NC_NC_NC);
CMCON = 7;

// setup_vref(FALSE);
CVRCON = 0;

i2c2k · Guest

thanks very much!
do you know in which version this problem is fixed?

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Those two problems were certainly fixed by vs. 3.222. I just did a
test compilation with that version and the .LST file code looks OK.
It was probably fixed a lot earlier than that, but I don't want to go through
and test a lot of different versions in order to find the exact one.
If you have a question about a certain version, post that version
and I'll check it.