Rainbow Electronics LM80 - Manual (Page 26)

Functional Description
(Continued)
12.8 Fan Divisor Register/RST_OUT/OS — Address 05h
Power on – < 7:4 > is 0101, and < 3:0 > is mapped to VID < 3:0 >
Bit Name Read/Write Description
0 FAN1 Mode
Select Read/Write A one selects the level sensitive input mode while a zero selects Fan count mode
for the FAN1 input pin.
1 FAN2 Mode
Select Read/Write A one selects the level sensitive input mode while a zero selects Fan count mode
for the FAN2 input pin.
2-3 FAN1 RPM
Control Read/Write FAN1 Speed Control.
< 3:2 > = 00 - divide by 1;
< 3:2 > = 01 - divide by 2;
< 3:2 > = 10 - divide by 4;
< 3:2 > = 11 - divide by 8.
If level sensitive input is selected: > 2 < = 1 selects and active-low input (An interrupt
will be generated if the FAN2 input is Low), > 2 < = 0 selects an active-high input (an
interrupt will be generated if the FAN2 input is High).
4-5 FAN2 RPM
Control Read/Write FAN2 Speed Control.
< 5:4 > = 00 - divide by 1;
< 5:4 > = 01 - divide by 2;
< 5:4 > = 10 - divide by 4;
< 5:4 > = 11 - divide by 8.
If level sensitive input is selected: < 2 > = 1 selects and active-low input (An interrupt
will be generated if the FAN2 input is Low), < 2 > = 0 selects an active-high input (an
interrupt will be generated if the FAN2 input is High).
6 OS pin enable Read/Write A one enables OS mode on the RST_OUT/OS output pin, while Bit 7 of this register
is set to zero. If bits 6 and 7 of this register are set to zero the RST_OUT/OS pin is
disabled.
7 RST enable Read/Write A one sets the RST_OUT/OS pin in the RST mode. In the RST mode, bit 7 of the
Fan Divisor/RST_OUT/OS Register has to be set to one. If bits 6 and 7 of this
register are set to zero the RST_OUT/OS pin is disabled.
12.9 OS Configuration/Temperature Resolution Register — Address 06h
Power on default Serial Bus address < 7:0 > = 0000 0001 binary
Bit Name Read/Write Description
0 OS status Read only Status of the OS.This bit mirrors the state of the RST_OUT/OS pin when in the OS
mode.
1 OS Polarity Read/Write A zero selects OS to be active-low, while a one selects OS to be active high. OS is
an open-drain output.
2 OS mode select Read/Write A one selects the one time interrupt mode for OS, while a zero selects comparator
mode for OS. (See in Section 7.0)
3 Temperature
Resolution
Control Read/Write A zero selects the default 8-bit plus sign resolution temperature conversions while a
one selects 11-bit plus sign resolution temperature conversions. 8-bit plus sign
conversions time is approximately 100 ms, while 11-bit plus sign conversion time is
approximately 2 seconds.
4-7 Temp [3:0] Read/Write The lower nibble (4 LSBs) of the 11-bit plus sign temperature data. < 4 > = Temp
[0] (nibble LSB, 0.0625˚C), < 5 > = Temp [1], < 6 > = Temp [2], < 7 > = Temp 3
(nibble MSB, 0.5˚C). For 8-bit plus sign temperature resolution, < 7 > = Temp [0]
(LSB, 0.5˚C) while < 4:6 > are undefined.
LM80
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