Calibre UK UCA93 - Manual (Page 10)

CALIBRE
Issue 1.0 Page 7
01/07/03
3.3. Function Description
3.3.1. Setup
Function specification int Setup(int OwnAddress, int ClockSpeed, int BusVoltage, int PullUpsOn, int
SlaveBlockTimeout)
Parameters are:
int ownaddress
This is the 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.
int ClockSpeed
This is the clock rate (bit rate for the I2C serial bus) when operating as a
master. For 400kHz enter 400, for 90kHz enter 90.
Maximum value 400 minimum value 25
int BusVoltage
The desired bus voltage multiplied by 100 e.g. 330 would give a bus voltage
3.3V. Please note that if a value between 4.2V and 5V is requested the output
will be 5V.
Maximum value 500 (5V) Minimum value 180 (1.8V).
int PullUpsOn
Set (1) to turn the pull up resistors on, clear (0) to turn them off.
int SlaveBlockTimeout
This parameter is only used by the slave block functions. If the Master has not
completed the transfer in this period (seconds) the Adapter will abort the
transfer and return an error code.
Range 1 – 255 seconds. NOTE: setting this value to 0 will prevent the Adapter
from timing out the slave block function.
Parameters returned If the software fails to find the driver error code 8000H is returned otherwise the
status is returned.
Prerequisites None.
Functional description This function initialises Adapter ready for I2C transfers.
3.3.2. SendAddress
Function specification Int SendAddress(int SlaveAddress, int SetNack)
Parameters are: int SlaveAddress
This is the address to be accessed via the I2C, e.g. A0H.
int SetNack
This controls whether the Adapter transmits an acknowledge down the I2C bus
on reception of a byte. The last byte received during a transfer must not be
acknowledged, in all other cases acknowledge must be enabled. If SetNack = 0
then acknowledge is enabled, if SetNack = 1 then acknowledge is disabled.
Normally there will be another transfer (data read or write) after the
SendAddress and so SetNack is enabled (0);
Parameters returned int ErrCode.
If the transfer time out occurs error code 8001H is returned otherwise the
status is returned.
Prerequisites The Adapter must be configured by running Setup.
Functional description The function waits for the bus to be free then sends the slave address.
The function waits for the address to be sent. Should a time-out occur during
the sending of an address then an error code 8001H is returned, otherwise the
status is returned.