Calibre UK PICA93LV Manual De Usuario
CALIBRE
Issue 1.3
Page 21
22/07/99
This is a period of time (in micro seconds) to wait for the required bus status.
If this time-out expires the I2C functions will exit returning an error code.
If this time-out expires the I2C functions will exit returning an error code.
int sclk
This is the clock rate (bit rate for the I2C serial bus) when operating as a
master.
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 initialise adapter ready for I2C
transfers.
4.4.5.
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 Parallel I2C Communications 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. Therefore, if a read (odd numbered) address is
being sent AND only 1 Byte is to be read, setnack should be set to = 1; in all
other cases it must be clear = 0.
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. Therefore, if a read (odd numbered) address is
being sent AND only 1 Byte is to be read, setnack should be set to = 1; in all
other cases it must be clear = 0.
Parameters returned
int ErrCode.
If the transfer time out occurs error code 8001H is returned otherwise the
status is returned.
status is returned.
Prerequisites
The adapter must be configured for PC and application 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.
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.
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.
the sending of an address then an error code 8001H is returned, otherwise
the status is returned.
4.4.6.
writebyte
Function specification
Int writebyte(int wrData)
Parameters are:
int wrData
This is the byte of data to be written.