LM64EVAL National Semiconductor, LM64EVAL Datasheet - Page 17

• Manufacturer Part Number: LM64EVAL
• Description: BOARD EVALUATION LM64
• Manufacturer: National Semiconductor

Specifications of LM64EVAL

• Sensor Type: Temperature, Fan Controller
• Sensing Range: 0°C ~ 85°C
• Interface: SMBus (2-Wire/I²C)
• Sensitivity: ±1°C
• Voltage - Supply: 3 V ~ 3.6 V
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: LM64
• Lead Free Status / RoHS Status: Not applicable / Not applicable

CONVERSION AND ONE-SHOT REGISTERS
ALERT STATUS AND MASK REGISTERS
ID REGISTERS
GENERAL PURPOSE REGISTERS
[RESERVED] REGISTERS — NOT USED
Register
2.0 LM64 Registers
04 (0A)
C0–FD
Note 15: For Register 0x1A the Power-On-Reset for the five LSB’s are the logic states present on the 5 GPIOx pins.
Note 16: For Register 0x1B the Power-On-Reset for the five LSB’s are the logic states present on the 5 GPDx pins.
2.3 LM64 INITIAL REGISTER SEQUENCE AND REGISTER DESCRIPTIONS IN FUNCTIONAL ORDER
The following is a Register Map grouped in functional and sequence order. Some address locations have been left blank to
maintain compatibility with LM86. Addresses in parenthesis are mirrors of named address for backwards compatibility with some
older software. Reading or writing either address will access the same 8-bit register.
2.3.1 LM64 Required Initial Fan Control Register Sequence
Important! The BIOS must follow the sequence below to configure the following Fan Registers for the LM64 before using any of
the Fan or Tachometer or PWM registers:
All other registers can be written at any time after the above sequence.
1C–1F
60–BE
22–2F
30–3F
40–45
[HEX]
Step
FE
0C
0F
FF
1A
1B
4E
02
16
06
15
17
18
20
1
2
3
4
5
Conversion Rate
One-Shot
ALERT Status
ALERT Mask
Manufacturer’s ID
Stepping/Die Rev. ID
General Purpose Input
General Purpose Output
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
[4A] Write bits 0 and 1; 3 and 4. This includes tach settings if used, PWM internal clock select (1.4 kHz or
360 kHz) and PWM Output Polarity.
[4B] Write bits 0 through 5 to program the spin-up settings.
[4D] Write bits 0 through 4 to set the frequency settings. This works with the PWM internal clock select.
Choose, then write, only one of the following:
A. [4F–5F] the Lookup Table, or
B. [4C] the PWM value bits 0 through 5.
If Step 4A, Lookup Table, was chosen and written then write [4A] bit 5 = 0.
(Continued)
Register Name
[Register]
HEX
17
and Setup Instructions
Read/Write
Read Only
Read Only
Read Only
Read Only
Write Only
R/W
R/W
R/W
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
POR Default
(Note 15)
(Note 16)
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[HEX]
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
A4
08
01
51