Calibre UK PICA93LV Manual De Usuario

Issue 1.3

 

Page 7

22/07/99

Each utility is documented in a standard format which lists its name, usage, function and effect on the
adapter is given. The adapter should be setup prior to any data transfer.

4.2.1.

I2C Setup / Initialisation Routine

Function definition:

void setup(int ownaddress, int sclk)

Usage:

setup(ownaddress, sclk);

Function:

procedure to set up Parallel I2C Communications Adapter.

Parameters are:

The address to which the adapter is to respond in slave mode. This forms the
upper 7 bits of the 8 bit address, the lowest bit being the Read(1) or Write(0)
bit. This means that if own = 0x57, the card will respond to a Write to address
0xAE and a Read to address 0xAF. Be sure not to select an address which is
already in use by any other device in your I2C system.

The SCL clock rate (bit rate for I2C serial bus).

Value of sclk

Approximate SCL (KHz)

0

90

1

45

2

11

3

1.5

Value Returned:

none.

I2C status on exit:

I2C status on exit from routine the Parallel I2C Communications Adapter will
have the serial interface enabled, also data reception acknowledge will be
enabled. The status register will contain 0x81 (assuming that no other
masters exist on the I2C system, if this is not the case then the contents of
the status register will also depend on externally generated bus activity).

Example Usage: (see also sample programs)

main()

{

int ownaddress, sclk;

ownaddress = 0x57;

/* Own slave address set to 0x57 (hex) */

sclk = 1;

/* Serial clock rate set to 45KHz */

setup(ownaddress, sclk);

printf("Parallel I2C Communications Adapter initialised\n");

}

/* This will set up the Parallel I2C Communications Adapter with */

/*an I2C slave address of 0xAE and a SCL clock rate of approximately 45KHz */