CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to CCS Technical Support
Some queries regarding multiple I2C buses...

 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
arunb



Joined: 08 Sep 2003
Posts: 492
Location: India

View user's profile Send private message Send e-mail

Some queries regarding multiple I2C buses...
PostPosted: Thu Feb 07, 2008 10:30 pm     Reply with quote
Hi,

MCU: 16F648A
Compiler: PCM 3.228

I am using 2 I2C buses, on two PICs, PIC1, PIC2

Each of the PICs are connected to two FRAMs F1 and F2

PIC1 is connected to Fram F1 and fram F2
PIC2 is connected to Fram F1 and Fram F2

A byte can be written to fram F1 using this code (it uses FRAM1_SDA and FRAM1_SCL)

Code:

#use i2c(master, sda=FRAM1_SDA, scl=FRAM1_SCL)
void write_fram1(int16 address,int8 data)
{
   
  //Code for I2C access of FRAM
}


similary a byte can be written to fram F2 using this code

Code:

#use i2c(master, sda=FRAM2_SDA, scl=FRAM2_SCL)
void write_fram2(int16 address,int8 data)
{

 //Code for I2C access of FRAM 
}


Now I would like to have a single function that writes a 16bit data to say on fram F1, so i would have a function like this

Code:

#use i2c(master, sda=FRAM1_SDA, scl=FRAM1_SCL)
void write_fram1_16bit(int16 address,int16 data)
{
  write_fram1(address,make8(data,1));
  write_fram1(address+1,make8(data,0));
 
}


These functions are accessed by another function say sl_process()

Code:

void sl_process()
{

 write_fram1_16bit(nAddress,nData);

}



Will the above function work ??

or do I have to call the write_fram1 function individully for each of the
bytes.

like this

Code:

void sl_process()
{

 write_fram1(nAddress,make8(nData,1));
 write_fram1(nAddress+1,make8(nData,0));

}


I observed that the above method works, but the write_fram1_16bit function does not.

Could anyone explain this.., is there something wrong with the usage of functions..and #use statement

Please help...

thanks
arunb
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

View user's profile Send private message

PostPosted: Fri Feb 08, 2008 12:16 pm     Reply with quote
The #use i2c() statement only affects the CCS i2c functions, such as
i2c_read() and i2c_write(), etc.

It does not affect higher level functions written by you, such as this one.
Quote:
#use i2c(master, sda=FRAM1_SDA, scl=FRAM1_SCL)
void write_fram1_16bit(int16 address,int16 data)
{
write_fram1(address,make8(data,1));
write_fram1(address+1,make8(data,0));

}


The #use i2c() statement causes the compiler to use the specified pins
in the i2c_read(), i2c_write(), etc., functions.
This is done at compile-time. It's not done at run-time.
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group