
Advanced Notebook I/O for ISA or LPC Designs
Datasheet
SMSC SIO10N268
Page 169
Rev. 0.5 (03-24-05)
DATASHEET
10.4.3 CR02
CR02 can only be accessed in the configuration state and after the CSR has been initialized to 02H.
Table 10.5 – CR02
UART Power
TYPE: R/W
DEFAULT: 0x00 on VCC POR and Hard Reset
BIT NO.
BIT NAME
DESCRIPTION
0
Reserved
Read Only. A read returns “0”.
1
UART3 Power
(
Note 10.9, Note 10.10)
A high level on this bit, allows normal operation of the Primary
Serial Port. A low level on this bit places the Primary Serial Port
into Power Down Mode (Default).
2
UART4 Power
(
Note 10.9, Note 10.10)
A high level on this bit, allows normal operation of the Primary
Serial Port. A low level on this bit places the Primary Serial Port
into Power Down Mode (Default).
3
UART1 Power
(
Note 10.9)
A high level on this bit, allows normal operation of the Primary
Serial Port. A low level on this bit places the Primary Serial Port
into Power Down Mode (Default).
4-6
Reserved
Read Only. A read returns “0”.
7
UART2 Power
(
Note 10.9, Note 10.10)
A high level on this bit, allows normal operation of the
Secondary Serial Port, including the SCE/FIR block. A low level
on this bit places the Secondary Serial Port including the
SCE/FIR block into Power Down Mode (Default).
Note 10.9
Power Down bits disable the respective logical device and associated pins, however the power down bit
does not disable the selected address range for the logical device. To disable the host address registers
the logical device’s base address must be set below 100h. Devices that are powered down but still
reside at a valid I/O base address will participate in Plug-and-Play range checking.
Note 10.10 The UART pins must be configured for their alternate function prior to enabling the UART power bits. In
addition, the IRCC should be configured for the appropriate mode of operation before the UART2 Power
bit is set. This is to ensure the state of the transmit and receive pins are in their inactive state for the
external device attached and for the internal block that has been enabled, respectively. The registers
used to configure the IRCC block are IR Output Mux bits located in the ECP FIFO Threshold/IR MUX
located at CR0A and the UART Mode register located at CR0C. These functions may also be configured
directly in the SCE registers located in the IR block. A description of these register may be found in the
SMSC Infrared Communication Controller (IRCC) specification.