5
Calibration Signature
At PROM address 2E (hex) and 2F (hex), a 16 bit word describes the state of the
handle. When the 16 bit word states “FACE”, the unit considers itself to be calibrated.
When the unit does not say “FACE”, and it should say “DEAD”, the unit considers itself
under calibration. When the unit is under calibration, it allows many faults to pass by
without writing these faults to the Status Register. The calibration system writes
“DEAD” to the signature addresses at the start of calibration, and when the unit is suc-
cessfully calibrated, it writes “FACE”. This is done just before the checksum is calcu-
lated on addresses 00 to 2F and placed in addresses 30 & 31 (hex).
6
Status Registers
At PROM address AC, AD and AE (hex) there are three status registers. The status
register at AC (hex) is a Slave processor history register. If a fatal error occurs with the
Slave, a bit is set in this register. AD (hex), is the Master status register, if there is a
problem with the Master, a bit is set in this register. When a fatal error bit is set in the
Slave register AE (hex) the Master sets the Slave Error bit and adds the Slave Error to
the Slave History Register. AE (hex) is the Slave Status Register, errors in the Slave
are placed here. This register can be changed or overwritten, but a history of errors is
kept in the Slave History Register.
Master Status Register (AD hex)
Failure Decode
O O O O X X X X
Master RAM test status
Slave Error
I
2
E
2
PROM calibration checksum status
Pressure Transducer Error
NA
NA
NA
NA
Slave Status Register (AE hex)
O O O O X X X X
Pressure Leak
Pressure Transducer Too High Error
Pressure Transducer Too Low Error
Home Motor Error
I
2
E
2
Bus Error
A/D Time-out Error
Slave RAM test status
Slave ROM test status
