Use of multiple i2c

[scanan]

Hello,

My question is about multiple use of i2c bus.
is it possible to define more than one i2c bus on a pic with CCS.
I am planning to use a 10 pcs of BH1750 light sensor at once. But the BH1750 has only 2 address meaning that I can use only 2 sensor on only one i2c bus.
How to use multiple i2c on CCS.

best regards

[Ttelmah]

Yes.
#USE I2C, just like #USE RS232, supports streams.
You can define as many I2C busses as you have pin pairs!.
CCS can develop master software I2C on any pins (provided they are not already doing something else).
Key is that once you use streams, you have to remember to use them everywhere. So i2c_start(), becomes i2c_start(your_first_stream) etc..
Each write, read, start, stop, needs the stream name added.
If you look at the manual entries for #USE I2C, and for each of the I2C functions, you will see the optional stream name entries.

Best Wishes

[scanan]

[Ttelmah]

Yes, but you really need MASTER, and the clock rate required for each stream.
So:

[scanan]

[scanan]

Hi,
Have problem passing stream to let say i2c_read(?)
how to pass stream to i2c library, thinkin I am goin to use 10 i2c

I tried something like that:
unsigned int16 e2promtimer=0;
const char s[2][10]={"bus1\0","bus2\0"};
unsigned int8 a,b,c,i,j;

#define EEPROM_SDA1 PIN_C7
#define EEPROM_SCL1 PIN_C6
#define EEPROM_SDA2 PIN_E2
#define EEPROM_SCL2 PIN_E5

#use i2c(master, sda=EEPROM_SDA1, scl=EEPROM_SCL1,stream=bus1,FAST=100000)
#use i2c(master, sda=EEPROM_SDA1, scl=EEPROM_SCL1,stream=bus2,FAST=100000)

the s array will be used to select i2c buses. but unable to pass the array let say to i2c_read(s[0]);

problem with this expression Get "stream must be a constant in the valid range " error

Any suggextions?
_________________
Dr Suleyman CANAN
R&D Electronic Engineer
https://suleymancanan.wordpress.com

Do whatever you do with amateur spirit -
But always feel professional.

[RF_Developer]

#use_i2c and the related i2c routines are not implemented at runtime. They are done at compile time. You cannot use a variable to select the stream. You must use a constant.

What happens is that the compiler substitutes code, some in-line, for the "calls", rather than the calls calling actual runtime routines. There is no runtime library; the code to be run/called has to be decided by the compiler.

So, the stream isn't a normal parameter. Instead of passing a variable for the stream, you have to do something else like using a switch statement:

[Ttelmah]

Yes.

You can thought take advantage of macro substitutions to make the actual routines simpler.

As a comment though, since the devices offer two addresses, five streams is all that should be needed.

So (showing just for I2C write):