Rainbow Electronics LM70 - Manual (Page 10)

1.0 Functional Description
(Continued)
1.5 INTERNAL REGISTER STRUCTURE
The LM70 has three registers, the temperature register, the
configuration register and the manufacturer’s/device identifi-
cation register. The temperature and manufacturer’s/device
identification registers are read only. The configuration reg-
ister is write only.
1.5.1 CONFIGURATION REGISTER
(Selects shutdown or continuous conversion modes):
(Write Only):
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
X X X X X X X X Shutdown
D0-D15 set to XX FF hex enables shutdown mode.
D0-D15 set to XX 00 hex enables continuous conversion
mode.
Note: setting D0-D15 to any other values may place the
LM70 into a manufacturer’s test mode, upon which the LM70
will stop responding as described. These test modes are to
be used for National Semiconductor production testing only.
See Section 1.2 Serial Bus Interface for a complete discus-
sion.
1.5.2 TEMPERATURE REGISTER
(Read Only):
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
MSB Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 LSB 1 1 1 X X
D0–D1: Undefined. TRI-STATE will be output on SI/0.
D2–D4: Always set high.
D5–D15: Temperature Data. One LSB = 0.25˚C. Two’s
complement format.
1.5.3 MANUFACTURER’S/DEVICE ID REGISTER
(Read Only):
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
1 0 0 0 0 0 0 1 0 0 0 0 0 0 X X
D0–D1: Undefined. TRI-STATE will be output on SI/0.
D2-D4: Always set LOW.
D5–D15: Manufacturer’s ID Data. This register is accessed
whenever the LM70 is in shutdown mode.
LM70
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