Trouble Getting Started

[totalnoob]

Hi, I am completely new to CCS C, I've been using sourceboost, I just installed the demo version of the CCS PIC C compiler and I'm having trouble getting started. I have mplab and a pic start plus programmer, what settings do I need so that I can begin programming chips. I'll be using a 16F877a.

Any help will be greatly appreciated, I need this for a school project that I'm behind schedule on.

[PCM programmer]

[totalnoob]

The demo came with a book I purchased, I didn't download it from CCS. I installed the demo and when I looked in the folder 'devices' the 16F877a.h file was there.

[PCM programmer]

It's possible that you have an older version of the demo. I recall that
in earlier years, the demo did support the 16F877A.

I need to know if the demo that you installed is the Windows IDE
CCS compiler or if it's the command-line compiler. Normally, the
"demo" is the full IDE. It looks like this:
http://www.ccsinfo.com/images/content/C_aware_editor.gif

But your book might have only included the command-line compiler.
That version of the compiler uses MPLAB as the IDE.

Which version of the compiler do you have ? Does it look like the
one in the screen-shot posted above ?

Also, what's the name of the book ?

[totalnoob]

Yes it does look like the screen shot. The window is the same, with PCW C Compiler IDE. The book is called Embedded C Programming and the Microchip PIC by Barnett, Cox & O'Cull. The book came with a sample program to get two pics to communicate via I2C. I'm trying to recreate that program for a 16F877a instead of a 16F877. Here's the code for each pic.

Master:
#include <16F877.h>
#use delay(clock=10000000)
#fuses HS,WDT
//set up i2c peripheral and use hardware SSP
#use i2c(Master,sda=PIN_C4,scl=PIN_C3,RESTART_WDT,FORCE_HW)

#int_TIMER1
TIMER1_isr()
{ //communicate every 50 ms
i2c_start(); //set i2c to start condition
i2c_write(0xa0); //send address
i2c_write(input_b()); //send master data from port B bits
i2c_start(); //restart to change data direction
i2c_write(0xa1); //address with direction bit changed
output_d(~i2c_read(0)); //get slave data and display
i2c_stop(); //stop i2c activity
}

void main()
{
setup_counters(RTCC_INTERNAL,WDT_1152MS);
setup_timer_1(T1_INTERNAL|T1_DIV_BY_1);
port_b_pullups(TRUE); //pull ups for input pins
enable_interrupts(INT_TIMER1);
enable_interrupts(global);
while(1)
{
//use WDT in case i2c 'hangs up' due to faulty slave
restart_wdt();
}
}

Slave:
#include <16F877.h>
#use delay(clock=10000000)
#fuses HS,NOWDT
#use i2c(SLAVE,sda=PIN_C4,scl=PIN_C3,address=0xa0)

enum {address,data};
int mode;

#int_SSP
SSP_isr()
{
int ch;
//check for valid char received. The interrupt occurs, but no
//valid character is received when setting up for the read
if (i2c_poll())
{
ch = i2c_read(); //get data received
//ch contains address on first transmission of the interchange
if (mode == address) mode = data; //so ignore and set for data byte
else //must be data byte
{
output_D(~ch); //output master data on LEDs
mode = address; //go back to waiting for address
}
}
//get to 'else' only if second command byte of intercahnge, so load
//i2c output register for read operation
else i2c_write(input_b()); //load for read
}


void main()
{
port_b_pullups(TRUE); //pullups on input bits
enable_interrupts(INT_SSP); //interrupt mode required
enable_interrupts(global);
mode = address; //set starting mode
while(1) //main does nothing
;
}


All I changed was the include file from 16F877 to 16F877a. Is there more that I need to change to implement this code on the 877a?

[PCM programmer]

[totalnoob]

Yes it compiled without error with the include 16F877A.h. When I created a new project for this code it asked me target device and I selected the PIC 16F877A. Then I copied the code from the book into the .c file and compiled it. The compiler didn't output a .asm file which mplab asks for, but I was able to take the .hex file from the compiler and program it to the PIC from mplab. However, the code doesn't work and I'm really not sure what I'm doing wrong because I'm very new to programming with PICs and I've never used I2C before.

[PCM programmer]

You need to add NOLVP to the #fuses statement for both Master and slave.
Also, it wouldn't hurt if you added BROWNOUT and PUT. Example:

[totalnoob]

Ok, added all those fuses, the NOLVP, BROWNOUT, And PUT. Still doesn't work. The SDA pins are connected together, the SCL pins are connected together. I have 4.7K pull-up resistors on both lines. And both pics are connected to the same ground and source.


P.S.
One other thing I changed was the clock=20000000 instead of 10000000 because I'm using a 20 MHz crystal to clock my pics.

[PCM programmer]

The comment for the Timer1 isr in your code says:

[totalnoob]

The version of my compiler is 3.170b.

[totalnoob]

Success!!!! Finally. I totally missed that timer change. Thanks a lot for your help. This is but a small step in my project, next I have to get this PIC to communicate with a motor controller via i2c to drive a robot. When that time comes I know who to ask for help.