MIC2591B Datasheet, PDF (24/34 Pages) Micrel Semiconductor – Dual-Slot PCI Express Hot-Plug Controller

MIC2591B
Detailed Register Descriptions
Converter Result Register (RESULT)
8-Bits, Read-Only
Conversion Result Register (RESULT)
D[7]
read-only
D[6]
read-only
D[5]
read-only
D[4]
read-only
D[3]
read-only
D[2]
read-only
Voltage or Current Data from ADC
D[1]
read-only
Bit
D[7:0]
Function
Measured data from ADC
read-only
Operation
Power-Up Default Value:
Read Command Byte:
xxxx xxxx_b = xx_h
0000 0000_b = 00_h
Micrel
D[0]
read-only
ADC Control Register (ADC_CNTRL)
8-Bits, Read/Write
ADC Control Register (ADC_CNTRL)
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
read-only
read-only
read-only
read/write read/write read/write
BUSY
Reserved
Reserved
SEL
PAR
D[1]
read/write
Supply Select
SUP[2:0]
D[0]
read/write
Bit(s)
BUSY
D[6]
D[5]
SEL
ADC status
Reserved
Reserved
A/D Slot Select
Function
PAR
Parameter control bit for ADC conversion
SUP[2:0] Supply select for ADC conversion
Operation
0 = ADC quiescent, 1 = ADC busy
Always read as zero
Always read as zero
Specifies slot for A/D conversion
0 = Slot A, 1 = Slot B
1 = Voltage, 0 = Current
000 = No conversion
001 = +3.3V supply
010 = Undefined - Do Not Use
011 = +12V supply
100 = Undefined - Do Not Use
101 = VAUX supply
Power-Up Default Value:
Command_Byte Value (R/W):
0000 0000_b = 00_h
0000 0001_b = 01_h
To operate the ADC, the ADC_CNTRL register must be ac-
cessed with the following parameters:
• Selection of which slot will provide the parameter
to be measured (Register Bit D[4])
• Choice of whether voltage or current is to be re-
ported (Register Bit D[3])
• Selection of the which supply that is to be monitored
(Register Bit D[2:0])
Note that this data may all be contained within one write to
the ADC_CNTRL register.
Software must then poll the BUSY bit (D[7]) until it is zero,
or wait for a period of 100ms. At the end of that time, the
RESULT register will contain the results of the conversion.
After reading the RESULT register, a new conversion may
be started.
March 2005
24
M9999-033105