Calibre UK IC Communication Adapter ICA93LV - Manual (Page 17)

Revision 1.7 Page 16 of 27
09/12/1999
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 I
2
C functions will exit returning an
error code.
sclk is clock rate (bit rate for the I
2
C 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 I
2
C
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)