Rainbow Electronics LM87 - Manual (Page 11)

Functional Description
(Continued)
2.1 Internal Registers of the LM87
TABLE 1. The internal registers and their corresponding internal LM87 addresses are as follows:
Register LM87 Internal Hex
Address
Power on
Value
Notes
Internal Temp. Hardware
High Limit
13h 0100 0110 70 ˚C Default - User adjustable. Lockable by setting bit
1 of register 4Ah.
External Temp. Hardware
High Limit
14h 0101 0101 85 ˚C Default - User adjustable. Lockable by setting bit
2 of register 4Ah.
Test Register 15h 0000 0000
Channel Mode Register 16h 0000 0000
Internal Temp. Hardware
High Limit
17h 0100 0110 70 ˚C Default - User adjustable.
External Temp. Hardware
High Limit
18h 0101 0101 85 ˚C Default - User adjustable.
Value RAM DAC Data
Register
19h 1111 1111 Defaults to full scale DAC setting.
Value RAM 1Ah-3Fh (See Section 13.18) Contains: monitoring results
(temperature, voltages, fan counts), WATCHDOG
limits, and Company/Stepping IDs
Company ID 3Eh 0000 0010 This designates the National Semiconductor LM87.
Revision 3Fh 0000 0110 Revisions of this device will start with 1 and increment
by one.
Configuration Register 1 40h 0000 1000
Interrupt Status Register 1 41h 0000 0000
Interrupt Status Register 2 42h 0000 0000
Interrupt Mask Register 1 43h 0000 0000
Interrupt Mask Register 2 44h 0000 0000
CI Clear Register 46h 0000 0000
VID0-3/Fan Divisor Register 47h 0101 XXXX The upper four bits set the divisor for Fan Counters 1
and 2. The lower four bits reflect the state of the
VID0-VID3 inputs.
VID4 Register 49h 1000 000X The lower bit reflects the state of VID4 input.
Configuration Register 2 4Ah 0000 0000
Interrupt Status Register 1
Mirror
4Ch 0000 0000
Interrupt Status Register 2
Mirror
4Dh 0000 0000
SMBALERT# Enable 80h 0010 0000
LM87
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