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+November 23, 2004
+
+The following specification describes the SMSC LPC47B397-NC sensor chip
+(for which there is no public datasheet available).  This document was
+provided by Craig Kelly (In-Store Broadcast Network) and edited/corrected
+by Mark M. Hoffman <mhoffman@lightlink.com>.
+
+* * * * *
+
+Methods for detecting the HP SIO and reading the thermal data on a dc7100.
+
+The thermal information on the dc7100 is contained in the SIO Hardware Monitor
+(HWM).  The information is accessed through an index/data pair.  The index/data
+pair is located at the HWM Base Address + 0 and the HWM Base Address + 1.  The
+HWM Base address can be obtained from Logical Device 8, registers 0x60 (MSB)
+and 0x61 (LSB).  Currently we are using 0x480 for the HWM Base Address and
+0x480 and 0x481 for the index/data pair.
+
+Reading temperature information.
+The temperature information is located in the following registers:
+Temp1		0x25	(Currently, this reflects the CPU temp on all systems).
+Temp2		0x26
+Temp3		0x27
+Temp4		0x80
+
+Programming Example
+The following is an example of how to read the HWM temperature registers:
+MOV	DX,480H
+MOV	AX,25H
+OUT	DX,AL
+MOV	DX,481H
+IN	AL,DX
+
+AL contains the data in hex, the temperature in Celsius is the decimal
+equivalent.
+
+Ex: If AL contains 0x2A, the temperature is 42 degrees C.
+
+Reading tach information.
+The fan speed information is located in the following registers:
+		LSB	MSB
+Tach1		0x28	0x29	(Currently, this reflects the CPU
+				fan speed on all systems).
+Tach2		0x2A	0x2B
+Tach3		0x2C	0x2D
+Tach4		0x2E	0x2F
+
+Important!!!
+Reading the tach LSB locks the tach MSB.
+The LSB Must be read first.
+
+How to convert the tach reading to RPM.
+The tach reading (TCount) is given by:  (Tach MSB * 256) + (Tach LSB)
+The SIO counts the number of 90kHz (11.111us) pulses per revolution.
+RPM = 60/(TCount * 11.111us)
+
+Example:
+Reg 0x28 = 0x9B
+Reg 0x29 = 0x08
+
+TCount = 0x89B = 2203
+
+RPM = 60 / (2203 * 11.11111 E-6) = 2451 RPM
+
+Obtaining the SIO version.
+
+CONFIGURATION SEQUENCE
+To program the configuration registers, the following sequence must be followed:
+1. Enter Configuration Mode
+2. Configure the Configuration Registers
+3. Exit Configuration Mode.
+
+Enter Configuration Mode
+To place the chip into the Configuration State The config key (0x55) is written
+to the CONFIG PORT (0x2E). 
+
+Configuration Mode
+In configuration mode, the INDEX PORT is located at the CONFIG PORT address and
+the DATA PORT is at INDEX PORT address + 1.
+
+The desired configuration registers are accessed in two steps: 
+a.	Write the index of the Logical Device Number Configuration Register
+	(i.e., 0x07) to the INDEX PORT and then write the number of the
+	desired logical device to the DATA PORT.
+
+b.	Write the address of the desired configuration register within the
+	logical device to the INDEX PORT and then write or read the config-
+	uration register through the DATA PORT.  
+
+Note: If accessing the Global Configuration Registers, step (a) is not required.
+
+Exit Configuration Mode
+To exit the Configuration State the write 0xAA to the CONFIG PORT (0x2E).
+The chip returns to the RUN State.  (This is important).
+
+Programming Example
+The following is an example of how to read the SIO Device ID located at 0x20
+
+; ENTER CONFIGURATION MODE   
+MOV	DX,02EH
+MOV	AX,055H
+OUT	DX,AL
+; GLOBAL CONFIGURATION  REGISTER 
+MOV	DX,02EH
+MOV	AL,20H
+OUT	DX,AL 
+; READ THE DATA
+MOV	DX,02FH
+IN	AL,DX
+; EXIT CONFIGURATION MODE     
+MOV	DX,02EH
+MOV	AX,0AAH
+OUT	DX,AL
+
+The registers of interest for identifying the SIO on the dc7100 are Device ID
+(0x20) and Device Rev  (0x21).
+
+The Device ID will read 0X6F
+The Device Rev currently reads 0x01
+
+Obtaining the HWM Base Address.
+The following is an example of how to read the HWM Base Address located in
+Logical Device 8.
+
+; ENTER CONFIGURATION MODE   
+MOV	DX,02EH
+MOV	AX,055H
+OUT	DX,AL
+; CONFIGURE REGISTER CRE0,   
+; LOGICAL DEVICE 8           
+MOV	DX,02EH
+MOV	AL,07H
+OUT	DX,AL ;Point to LD# Config Reg
+MOV	DX,02FH
+MOV	AL, 08H
+OUT	DX,AL;Point to Logical Device 8
+;
+MOV	DX,02EH 
+MOV	AL,60H
+OUT	DX,AL	; Point to HWM Base Addr MSB
+MOV	DX,02FH
+IN	AL,DX	; Get MSB of HWM Base Addr
+; EXIT CONFIGURATION MODE     
+MOV	DX,02EH
+MOV	AX,0AAH
+OUT	DX,AL