Rainbow Electronics LM41 - Manual (Page 21)

2.0 Register Set
(Continued)
Temperature Data Format (Continued)
Temperature Binary Hex
-255.5 ˚C 10 0000 0001 201h
-256 ˚C 10 0000 0000 200h
2.9.4 Temperature Control (Addr: 001 010; 0Ah)
This register is set to the reset value by a Device Reset.
Reg
Add
Register
Name
R/
W
P
O
R
Val
Bit
15
MSb
Bit
14
Bit
13
Bit
12
Bit
11
Bit
10
Bit
9
Bit
8
Bit
7
Bit
6
Bit
5
Bit
4
Bit
3
Bit
2
Bit
1
Bit
0
LSb
001 010
Temperature
Control
R/
W
0h
Reserved
EN1 EN0 ATE
0 0 0 0 0 0 0 0 0 0 0 0
Bit Type Description
0 R/W ATE (Attention Enable). When set, this bit enables an Attention Request signal to be generated by the
LM41, if the EN0, EN1 or EN2 bits of this register are set.
0: Attention Request disabled (from enabled Temperature Sensor- default)
1: Attention Request enabled (from enabled Temperature Sensor)
1 R/W EN0 (Enable Sensor 0). When this bit is set, the Local Temperature Sensor is enabled for temperature
measurements.
0: Temperature Sensor disabled (default)
1: Temperature Sensor enabled
2 R/W EN1 (Enable Sensor). When this bit is set, the Remote Thermal Diode Temperature Sensor is enabled for
temperature measurements.
0: Temperature Sensor disabled (default)
1: Temperature Sensor enabled
15-3 RO Reserved. Will always read "0".
2.10 VOLTAGE-ONLY MEASUREMENT FUNCTION (TYPE 0010)
This section defines the register structure and operation of the Voltage-Only Measurement Function. The FuncDescriptor value
of this function is ‘0010’.
2.10.1 Operation
The Voltage-Only measurement function is capable of measuring the voltage of voltage measurement points ("sensors"). These
may be general or dedicated inputs (e.g., for backup battery measurement or the supply voltage to the device). The measurement
of all the enabled voltage sensors is cyclic and continuous.
Sensor Scan The control register of the function defines which voltage sensors (inputs) are included in the scan. A sensor is
scanned only if it is enable by the Sensor Enable bit (EN0, EN1, EN2, EN3 and EN4). The sensors are scanned in an ascending,
round-robin order, based on the sensor number. Disable sensors are skipped and the next enabled sensor in ascending order is
scanned.
The minimum scan rate is recommended to be 4Hz (i.e., the measurement data is updated at least once in 250 ms), see Section
2.11 for further details. In Low-Power Mode, the scan rate is four times lower than the scan rate in Active Mode. The scan rate
effects the bus bandwidth required to read the results. The sampling rate of the voltage measurements can also be controlled via
the Conversion Rate register, see Section 2.11 for further details.
Data Readout When a new result is stored in the Readout register a Function Event is generated. Reading the Readout register
clears the Status Function 2 flag (SF2) for the Voltage-Only Measurement Function in the Device Status register. The result is
available in the Readout register waiting for the master to read it during the master sensor read sequence. The device should
delay or buffer additional conversions to allow the master time to read the result (see Sensor Scan Rate Section 2.11). If a new
result is ready before the previous result has been read, the new results overwrites the previous result and the Error Function 2
flag (ERF2) for the Voltage-Only function in the Device Status register is set (indicating an overrun event). Reading the
Voltage-Only Measurement Readout register clears also the ERF2 flag.
Readout Resolution The resolution of the readout register is defined in the Voltage Capabilities register. The resolution of the
LM41 is fixed and cannot be modified by software. The voltage readout format is common to all voltage sensors and is 9-bits
unsigned. For over or under input voltage conditions the data is guaranteed to saturate at all "1"s or "0"s so long as Operating
Ratings of the LM41 are adhered to.
LM41
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