Battery Backed Static RAM
Battery Backed Static RAM
The
The BBSRAM is located at the absolute address of (0x08000000) in one continuous 2 MB block.
Serial Ports
The
COM3 and COM4 can be operated in
Interrupt assignment for each COM port is handled in CMOS Setup, and each port can be independently enabled or disabled.
All four serial ports are protected against ESD damage. This protection exceeds 15KV human body model.
COM PORT CONFIGURATION
There are no configuration jumpers for COM1 and COM2 because it only operates in
Jumper V2 is used to configure COM3 and COM4 for
COM3 AND COM4
The TxD+/TxD– differential line driver can be turned on and off by manipulating the DTR handshaking line.
The following code example shows how to turn the line driver for COM3 on and off:
mov | dx,03ECh | ; Point to COM3 Modem Control register |
in | al,dx | ; Fetch existing value |
or | al,01h | ; Clear bit D0 |
out | dx,al | ; Turn DTR on (enables line driver) |
in | al,dx | ; Fetch existing value |
and | al,0FEh | ; Set bit D0 |
out | dx,al | ; Turn DTR off (disables line driver) |
Reference – 27 |