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XP8500
Software Reference s 43
• int adc4_compute( struct adc4coeff cnvrsn,
int data1, float volt1, int data2,
float volt2 )
Computes the
zero_offset
and
invgain
for the
adc4coeff
structure pointed to by
cnvrsn
. The function computes the constants
zero_offset
and
invgain
based on A/D readings of two known
input voltages to allow input data to be corrected later using the
formula
voltage =
invgain
* (
zero_offset
– data) .
data1
is the raw A/D reading for the known input voltage
volt1
.
data2
is the raw A/D reading for the known input voltage
volt2
.
RETURN VALUE: 0 if the constants are computed successfully, –1 if
the data used resulted in divide by zero while computing the constants.
• int adc4_eerd( unsigned int board_adr,
int address )
Reads byte data from EEPROM data
address
.
board_adr
is the physical address of the XP8500 board, defined as
0000 1100 ppxy. Addresses range from 0 to 511 for the 512 bytes of
EEPROM memory storage.
RETURN VALUE: non-negative value for data, –1 if the XP8500
board cannot be found, –2 if a problem occurs while accessing the
EEPROM.
• int adc4_eewr( unsigned int board_adr,
int address, char data )
Writes byte
data
to EEPROM data
address
.
board_adr
is the physical address of the XP8500 board, defined as
0000 1100 ppxy.
address
is 0 to 511 for the 512 bytes of EEPROM memory storage.
The top 256 bytes can be write-protected using with jumpers on
header J3.
RETURN VALUE: 0 if the data is successfully written to the
EEPROM, –1 if the XP8500 board cannot be found, –2 if a problem
occurs while accessing the EEPROM, –3 if a write to the top 256
bytes of EEPROM was attempted while the write-protect jumper is
connected.