15
3.3 EEPROM Storage
3.3.1 EEPROM Format
The IPT transducer uses a 2 Kbit serial EEPROM from
Microchip
, P/N 25LC020AT-E/MC.
The EEPROM is organized as 256 x 8. Reads/w
rites to the EEPROM should be per the manufacturer’s
data sheet. Note: values are stored
“big-endian”; most significant bit first.
3.3.2 Contents
3.3.2.1 Pressure Correction Coefficients
The 37 correction coefficients (
A
through
fa6
) are stored in 32-bit IEEE 754 format in
locations
00
through
93
.
Example:
-7.2467064 = C0E7E504
3.3.2.2 Full Scale Pressure Range
The IPT full scale pressure range (
FS
) is stored in 32-bit IEEE 754 format in locations
94
through
97
.
Example:
20 = 41A00000
3.3.2.3 Minimum/Maximum Operating/Storage Temperature Limits
IPT operating/storage temperature limits (
Min/Max Op/Stor Temp)
are stored as 8-
bit signed integers in locations
98
through
9B
.
Examples:
Min Operating
-40 = D8
Max Operating
85 = 55
Min Storage
-55 = C9
Max Storage
125 = 7D
3.3.2.4 Minimum Pressure Output
The minimum pressure output value (
Pmin
) is the minimum value observed from the
pressure channel ADC over the IPT operating temperature/pressure range and is stored
as a 24-bit unsigned integer. Location
9C
is padded with
00
and
Pmin
is stored in
locations
9D
through
9F
.
Example:
1213487 = 12842F
3.3.2.5 Maximum Pressure Output
The maximum pressure output value (
Pmax
) is the maximum value observed from the
pressure channel ADC over the IPT operating temperature/pressure range and is stored
as a 24-bit unsigned integer. Location
A0
is padded with
00
and
Pmax
is stored in
locations
A1
through
A3
.
Example:
11021407 = A82C5F