Calibre UK PICA93LV user manual Int getbytesint far *transferarray, Int nobytesread

CALIBRE

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	When all the bytes have been transmitted a stop is issued and the total
	number of bytes is returned.
	Sendbytes can only be used in master write mode.
4.4.13. getbytes
Function specification	Int getbytes(int far *transferarray)
Parameters are:	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 detail.
2	nobytes	The number of bytes (n) to be sent. Min value 1.
3	byte 0	First byte read.
		"
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	byte n	Last byte read.
Parameters returned	int nobytesread
	The number of bytes actually read.
Prerequisites	Adapter must be configured using setup. Array elements 0, 1 and 2 must be
	initialised. Elements 3 to n do not need to be initialised since they are where
	the read data is returned. The array must be pre-defined to a size at least
	large enough to hold all the parameters and data concerned.
Transmission Format	If the slaveaddress has the least significant bit set (1) then this forms a read
	address, if the least significant bit is clear (0) then this forms the write
	address e.g. A0H is the write address and A1H is the associated read
	address.

getbytes supports two transfer formats these being:

i.start-slavereadaddress-byte(s)-stop

To select transfer format i) pass the read address as slaveaddress. The wordaddress is not used in this format and is ignored by getbytes.

ii.start-slavewriteaddress-wordaddress-restart-slavereadaddress-byte(s)- stop

To select transfer format ii) pass the write address as slaveaddress. In this format the wordaddress must be valid.

wordaddress is pointer to the first byte of data to be read.

nobytestoread is the number of bytes to be read. The minimum value allowable is 1.

Issue 1.3 Page 25

22/07/99