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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/writes 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
3.3.2.2 Full Scale Pressure Range
3.3.2.3 Minimum/Maximum Operating/Storage Temperature Limits
3.3.2.4 Minimum Pressure Output
3.3.2.5 Maximum Pressure Output
The 37 correction coefficients (A through fa6) are stored in 32-bit IEEE 754 format in
locations 00 through 93.
Example: -7.2467064 = C0E7E504
The IPT full scale pressure range (FS) is stored in 32-bit IEEE 754 format in locations 94
through 97.
Example: 20 = 41A00000
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
Max Operating
Min Storage
Max Storage
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
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
-40 = D8
85 = 55
-55 = C9
125 = 7D
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