Revision 1.7 Page 18 of 27
09/12/1999
getstatus
Function specification: Int getstatus ( )
Parameters returned I2Cstatus, the current value of the bus status.
Prerequisites Adapter must be configured using setup.
Functional description The function reads status word from the adapter and returns it.
recover
Function specification: Int recover
Parameters returned ErrCode. If the bus recovery failed error code 8006H is returned
otherwise the status is returned.
Prerequisites Adapter must be configured using setup.
Functional description This function issues two consec utive stop comm ands on the bus, with a
delay in between. It then clears the adapter registers and reads the
status. This should normally set the adapter into a known idle state when
a bus error or other problem has occurred.
If the status does not indicate bus free or the Bus Error bit is still set then
8006H is returned otherwise the status is returned.
sendbytes
Function specification Int sendbytes (int far *transferarray)
The far pointer must point to a single dimensional array the format of which is detailed below. The calling
function must have initialised elements 0, 1 and 2 prior to calling the function.
Element no Element name Description
0 slaveaddress Slaveaddress is the address to be accessed via the I2C
Bus, this is in hexadecimal e.g. A0H.
1 wordaddress Wordaddress is the offset within the slave to which the
first byte of data is to be written, see transmission format
for more details.
2 nobytes The number of bytes (n) to be sent. Min value 1.
3 byte 0 First byte to be sent.
“
“
byte n Last byte to be sent.
Parameters returned bsent, the number of bytes actually sent.
Prerequisites Adapter must be configured using setup. Array elements 0, 1 and 2
must be initialised. Usually elements 3 to n would also be initialised.
Array must be pre-defined to a size at least large enough to hold all the
parameters and data concerned.
Transmission format There are two transmission formats, these are:
i. start-slaveaddress-byte(s)-stop
If transmission format i.) is required set the wordaddress to a number greater than FFH.
ii. start-slaveaddress-wordaddress-byte(s)-stop
If transmission format ii.) is required set the wordaddress to a number less than or equal to FFH.
Functional description The function determines the required tr ansmission format and then
sends a start code and the slave address. If transmission format ii) has
been selected the wordaddress is sent.
The data bytes are then transmitted sequentially.
Should a time-out occur or he slave not acknowledge a transfer the
transmission is terminated by a stop and the number of bytes actually
transmitted is returned.