Sendaddress

baseaddress is the address at which the adapter has been installed, e.g. 310H

ownaddress I2C 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 ownaddress = 57H the card will respond to a write address of AEH and a read address of AFH.

Statuswait is a period of time (in microseconds) to wait for the required bus status. If this time-out expires the I2C functions will exit returning an error code.

sclk is clock rate (bit rate for the I2C serial bus) when operating as a master.

Value of sclk	Approximate SCL-kHz
0	90
1	45
2	11
3	1.5

Parameters returned	none.
Prerequisites	none.
Functional description	This function characterises the PC and initialises adapter ready for I2C
	transfers.
sendaddress
Functional specification	Int sendaddress (int slaveaddress, int setnack)
	slaveaddress is the address to be accessed via the I2C, e.g. A0H
	setnack 1 for no acknowledge 0 for acknowledge – see Functional
	Description
Parameters returned	ErrCode. If the transfer time out occurs error code 8001H is returned
	otherwise the status is returned.
Prerequisites	adapter must be configures by running setup.
Functional description	The function waits for the bus to be free. Then sends the slave address
	with the appropriate acknowledge.
	The acknowledge is set ready for the data transfer after the address and
	hence in read mode (odd address being sent) if only one byte is to be
	read the setnack parameter must equal 1. If more than one byte is to be
	read or if in write mode (even address being sent) then setnack must
	equal 0.
writebyte
Function specification	Int writebyte (int wrData)
	wrData is the byte of data to be written.
Paramteres returned	ErrCode. If the transfer time out occurs error code 8004H is returned
	otherwise the status is returned.
Prerequisites	Adapter must be configured using setup, start and write address sent by
	sendaddress.
Functional description	The function writes the data to the adapter and then waits for it to be
	sent. Should a time-out occur during the sending of the data then error
	code 8004H is returned, otherwise the status is returned. Writebyte is
	compatible with both master write and slave write modes.
readbyte
Function specification	Int readbyte (int setnack)
Revision 1.7	Page 16 of 27
09/12/1999

writebyte

readbyte