REGISTER
Device ID
ADDRESS
DESCRIPTION
STATE
0x20 R
A read only register which provides device identification.
Bits[7:0] = 0x4C when read
C
Hard wired
= 0x4C
Device Rev
0x21 R
A read only register which provides device revision
information. Bits[7:0] = 0x00 when read
C
C
Hard wired
= 0x00
PowerControl
0x22 R/W
Bit[0] FDC Power
Bit[1] Reserved
Default = 0x00.
on Vcc POR or
Reset_Drv
Bit[2] Reserved
Bit[3] Parallel Port Power
Bit[4] Serial Port 1 Power
Bit[5] Serial Port 2 Power
Bit[6] Reserved
hardware signal.
Bit[7] Reserved
= 0
= 1
Power off or disabled
Power on or enabled
Power Mgmt
0x23 R/W
Bit[0] FDC
C
Bit[1] Reserved
Default = 0x00.
on Vcc POR or
Reset_Drv
Bit[2] Reserved
Bit[3] Parallel Port
Bit[4] Serial Port 1
Bit[5] Serial Port 2
Bit[6] Reserved (read as 0)
Bit[7] Reserved (read as 0)
hardware signal
= 0
= 1
Intelligent Pwr Mgmt off
Intelligent Pwr Mgmt on
OSC
0x24 R/W
Bit[0] Reserved
C
Bit [1] PLL Control
Default = 0x04,
on Vcc POR or
Reset_Drv
= 0
PLL is on (backward Compatible)
= 1
PLL is off
Bits[3:2] OSC
hardware signal.
= 01
= 10
= 00
= 11
Osc is on, BRG clock is on.
Same as above (01) case.
Osc is on, BRG Clock Enabled.
Osc is off, BRG clock is disabled.
Bit [6:4] Reserved, set to zero
Bit[7] IRQ8 Polarity
= 0
= 1
IRQ8 is active high
IRQ8 is active low
Chip Level
0x25
Reserved - Writes are ignored, reads return 0.
Vendor Defined
167
SMSC [ SMSC CORPORATION ]
