Справочник Пользователя для Calibre UK PICA93LV
CALIBRE
Issue 1.3
Page 14
22/07/99
4.3.
QBASIC Routines
4.3.1.
I2C Setup/Initialisation Routines
Function definition:
setup (ownaddress as integer, sclk as integer)
Usage
call setup(ownaddress as integer, sclk as integer)
Function:
procedure to set up Parallel I2C Communications Adapter.
Parameters are:
ownaddress%
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% = &h57, the card will respond to a Write
to address &hAF. Be sure not to select an address which is already in use by
any other device in your I2C system. If ownaddress% &h00 the adapter will
monitor all I2C bus information but will not affect any data transfers, thus
acting as a bus monitor.
upper 7 bits of the 8 bit address, the lowest bit being the Read(1) or Write (0)
bit. This means that if ownaddress% = &h57, the card will respond to a Write
to address &hAF. Be sure not to select an address which is already in use by
any other device in your I2C system. If ownaddress% &h00 the adapter will
monitor all I2C bus information but will not affect any data transfers, thus
acting as a bus monitor.
sclk%
the SCL clock rate (bit rate for I2C serial bus).
Value of sclk%
Approximate SCL (KHz)
0
90
1
45
2
11
3
1.5
Value Returned:
none.
I2C status on exit:
I2C status on exit from routine the Parallel I2C Communications Adapter will
have the serial interface enabled, also data reception acknowledge will be
enabled. The status register will contain 0x81 (assuming that no other
masters exist on the I2C system, if this is not the case then the contents of
the status register will also depend on externally generated bus activity).
have the serial interface enabled, also data reception acknowledge will be
enabled. The status register will contain 0x81 (assuming that no other
masters exist on the I2C system, if this is not the case then the contents of
the status register will also depend on externally generated bus activity).
Example Usage:
(see also sample programs)
' This will set up the Parallel I2C Communications Adapter with an I2C slave address of &HAE and a
SCL clock rate of approximately 45KHz
SCL clock rate of approximately 45KHz
sub main
ownaddress% = &h57
' Own slave address set to &h57 (hex)
sclk% = 1
' Serial clock rate set to 45KHz
call setup(ownaddress%, sclk%)
print"Parallel I2C Communications Adapter initialised"
end sub
4.3.2.
I2C Status Checking Routine
Function definition:
getstatus%()
Usage:
I2Cstatus% = getstatus
Function:
function to read status register of Parallel I2C Communications Adapter.
Parameters are:
None.
Value Returned:
i2cstatus%
where i2cstatus is an integer from &H00 to &HFF which indicates the current
status of the PICA93LV.
status of the PICA93LV.