Rainbow Electronics DS2422 - Manual (Page 15)

DS2422
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threshold registers that are associated to the serial data input. The registers for data alarm thresholds are
located at address 020Ah (Low Alarm) and 020B (High Alarm). The comparison is based on the most
significant serial input byte and assumes that the data is represented as unsigned binary number.
TEMPERATURE SENSOR ALARM
The DS2422 has two Temperature Alarm Threshold registers (address 0208h, 0209h) to store values, which
determine whether a critical temperature has been reached. A temperature alarm is generated if the device
measures an alarming temperature AND the alarm signaling is enabled. The bits ETLA and ETHA that enable the
temperature alarm are located in the Temperature Sensor Control Register. The temperature alarm flags TLF and
THF are found in the Alarm Status Register at address 0214h.
Temperature Sensor Control Register Bitmap
ADDR b7 b6 b5 b4 b3 b2 b1 b0
0210h 0 0 0 0 0 0 ETHA ETLA
During a mission, there is only read access to this register. Bits 2 to 7 have no function. They always read 0 and
cannot be written to 1.
Register Details
BIT DESCRIPTION BIT(S) DEFINITION
ETLA: Enable Tempera-
ture Low Alarm
b0
This bit controls whether, during a mission, the Temperature Low
Alarm Flag TLF may be set, if a temperature conversion results in a
value equal to or lower than the value in the Temperature Low Alarm
Threshold Register. If ETLA is 1, temperature low alarms are enabled.
If ETLA is 0, temperature low alarms are not generated.
ETHA: Enable
Temperature High Alarm
b1
This bit controls whether, during a mission, the Temperature High
Alarm Flag THF may be set, if a temperature conversion results in a
value equal to or higher than the value in the Temperature High Alarm
Threshold Register. If ETHA is 1, temperature high alarms are
enabled. If ETHA is 0, temperature high alarms are not generated.
SERIAL INPUT ALARM
The DS2422 has two Data Alarm Threshold registers (address 020Ah, 020Bh) to store values, which determine
whether data read through the serial interface can generate an alarm. Such an alarm is generated if the input data
qualifies for an alarm AND the alarm signaling is enabled. The bits EDLA and EDHA that enable the serial input
alarm are located in the DATA_IF Control Register. The corresponding alarm flags DLF and DHF are found in the
Alarm Status Register at address 0214h.
DATA_IF Control Register Bitmap
ADDR b7 b6 b5 b4 b3 b2 b1 b0
0211h 1 1 1 1 1 1 EDHA EDLA
During a mission, there is only read access to this register. Bits 3 to 7 have no function. They always read 1 and
cannot be written to 0.