REGISTER
Device ID
ADDRESS
DESCRIPTION
STATE
0x20 R
A
read only register which provides device
C
identification. Bits[7:0] = 0x44 when read
Hard wired
= 0x44
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 Power off or disabled
= 1 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
hardware signal
Bit[5] Serial Port 2
Bit[6] Reserved (read as 0)
Bit[7] Reserved (read as 0)
= 0 Intelligent Pwr Mgmt off
= 1 Intelligent Pwr Mgmt on
OSC
0x24 R/W
Bit[0] Reserved
C
Bit [1] PLL Control
= 0 PLL is on (backward Compatible)
= 1 PLL is off
Bits[3:2] OSC
= 01 Osc is on, BRG clock is on.
= 10 Same as above (01) case.
= 00 Osc is on, BRG Clock Enabled.
= 11 Osc is off, BRG clock is disabled.
Default = 0x04,
on Vcc POR or
Reset_Drv
hardware signal.
Bit [6:4] Reserved, set to zero
Bit[7] IRQ8 Polarity
= 0 IRQ8 is active high
= 1 IRQ8 is active low
Chip Level
0x25
Reserved - Writes are ignored, reads return 0.
Vendor Defined
177
SMSC [ SMSC CORPORATION ]
