Calibre UK ICA93LV user manual Write Data Byte to Slave Routine

setnack%	this controls whether the I2C Communications Adapter transmits and
	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 the LAST BUT ONE byte is to be
	read, setnack% should be set to =1; in all other cases it must be set = 0. (In the
	case of reading 1 byte only, acknowledge will have been disabled by
	sendaddress and so should now be enabled again after reading the data, hence
	setnack% = 0 for reading a single byte of data.)
Value Returned:
<databyte%>	the function reads the byte of data and returns an integer equal to the value read.

I2C status on exit from routine:

	The status of the I2C/ the Communications Adapter will be either &h00 - bus the
	busy and unread data in the data register or &h80 - bus busy and no unread data
	in the data register	depending on whether any more bytes of data have
	been transmitted by the slave device which is being read. (See Appendix A for
	details of Status Codes).
Example Usage:	(see also sample programs)
$include”i2c.inc”	‘* This contains the I2C routines *
baseaddr% = &h310	‘* Adapter’s base address = 310 (hex) *
setnack% = 0	‘* Enable Acknowledge - only one byte is to be read *

‘* (see parameter descriptions) *

databyte% = FNreadbyte%(baseaddr%, setnack%) print “Data read was “;databyte%

‘* This will read a byte of data from a slave previously addressed by and with acknowledge already * ‘* disabled by sendaddress. After reading the data, acknowledge will be re-enabled.*

5.2.5.Write Data Byte to Slave Routine

Name:	writebyte(baseaddr%, databyte%)
Usage:	call writebyte(baseaddr%, databyte%)
Function:	procedure to write a byte of data to a slave device whose slave address has
	already been sent by sendaddress.
Parameters are:
baseaddress%	the base address of the I2C Communications Adapter set by links on circuit
	board.
databyte%	the byte of data which is to be written to the slave device.
Value Returned:none.

I2C status on exit from routine:

	The status of the I2C Communications Adapter will be &h00 - bus busy and data
	in the data register transmitted successfully. (See Appendix A for details of
	Status Codes).
Example Usage:	(see also sample programs)
$include “i2c.inc”	‘* This contains the I2C routines *
baseaddr% = &h310	‘* Adapter’s base address = 310 (hex) *
databyte% = &h69	‘* Data byte which is to be transmitted*

call writebyte(baseaddr%, data byte%) print”Data has been transmitted”

‘* This will write a byte of data to a slave previously addressed by sendaddress. *

5.2.6.Send an I2C Stop Routine

Name:	sendstop(controladdress%)
Usage:	call sendstop (controladdress%)
Revision 1.7	Page 13 of 27
09/12/1999