CALIBRE
USING THE UTILITIES
4.1.Introduction
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.C Routines
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: | int ownaddress |
|
| 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. | |
| int sclk |
|
| 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 */
Issue 1.3 | Page 7 |
22/07/99