PCM-C418/Configuration
v1.0
www.winsystems.com
Page 29
Default = 0x05 = RS232 Enabled
•
485TE - Selects the Transmit Enable signal in RS-422/485 mode; 1=TXD enable,
0=RTS enable
Default = 0 = RTS enable
•
SLEW - Limit slew rate to 250 kbps
Default = 0 = Max data rate
•
TERM - Enables RS-422/485 terminations
Default = 0 = Disabled
•
EN - Enables the SP339 multimode UART
Default = 1 = Enabled
MODE - Selects the communication mode of the serial port (set in BIOS and should be
maintained).
Example:
Set COM3 to RS-485 Auto with termination and COM4 RS-422 Auto with
SKEW:
Write 0x01 to 0x1E9
Points to COM3-4 Mode controls
Write 0x2E to 0x1EA
COM3 - 485TE, TERM2, EN1, MODE 2
Write 0x37 to 0x1EB
COM2 - 485TE, SLEW2, EN2, MODE 3
Table 17:
Register (0x1EB) for COM4
D7
D6
D5
D4
D3
D2
D1
D0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
X
X
485TE
SLEW2
TERM2
EN2
UART2 mode (0-3)
Table 18:
Modes
Mode
Description
0
LOOPBACK
1
RS232
2
RS485
3
RS422
