SCH3112I-NE SMSC [SMSC Corporation], SCH3112I-NE Datasheet - Page 111

• Manufacturer Part Number: SCH3112I-NE
• Description: LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
• Manufacturer: SMSC [SMSC Corporation]

LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
Datasheet
SMSC SCH311X
8.3
SCH3116
DEVICE
The purpose of this function is to save the effort to deal with direction control in software. A direction
control signal (usually nRTS) is used to tristate the transmitter when no other data is available, so that
other nodes can use the shared lines. It is preferred to have this function on all six serial ports.
This will affect the nRTS and nDTR signals for each serial port in the device. Each serial port will have
the following additional characteristics:
■
RS485 Auto Direction Control
Table 25.1
page 286
SHARE
An option register for the serial port in the runtime registers with following bits:
An enable bit to turn on/off the direction control
An enable bit to select which bit nRTS or nDTR, of the serial port is affected.
A bit to select the polarity - high or low, that the selected signal is driven to when the output buffer
of the corresponding serial port is empty or full.
MODE
(0XF0)
REG
BIT6
ALL
2 on
SP1
BIT
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Table 8.8 SCH311X IRQ Sharing Summary (continued)
Table 25.1
page 286
SHARE
MODE
(0XF0)
SP12
REG
BIT7
2 on
SP1
BIT
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Table 25.1
page 289
SHARE
MODE
(0XF0)
SP34
REG
BIT7
6 on
SP3
BIT
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
DATASHEET
95
Table 25.1
page 290
SHARE
MODE
(0XF0)
SP56
REG
BIT7
8 on
SP5
BIT
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
SP1
S12
S12
S12
S12
S12
S12
S12
S12
345
NS
NS
NS
NS
NS
NS
NS
NS
34
56
6
SP2
S12
S12
S12
S12
S12
S12
S12
S12
345
NS
NS
NS
NS
NS
NS
NS
NS
34
56
6
SP3
S34
S34
S34
S34
S34
S12
S34
S12
345
NS
NS
NS
NS
NS
NS
NS
NS
34
56
6
SP4
S34
S34
S34
S34
S34
S12
S34
S12
345
NS
NS
NS
NS
NS
NS
NS
NS
34
56
6
Rev 0.2 (09-28-04)
SP5
S56
S56
S56
S56
S56
S12
S34
S12
345
NS
NS
NS
NS
NS
NS
NS
NS
56
56
6
SP6
S56
S56
S56
S56
S56
S12
S34
S12
345
NS
NS
NS
NS
NS
NS
NS
NS
56
56
6