452
External Controllers
© Tibbo Technology Inc.
#5
Ground
#6
DSR
(input)
#7
RTS
(output)
#8
CTS
(input)
#9
DS1101
The DS1101 features a multi-channel RS232 port. Physically, the port is
implemented as a single DB9M connector with three output lines, four input lines,
, and the ground.
Internally, the DS1101 has four independent serial ports. These are controlled
through the ser. object (see TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual).
Each of the four ports has its own TX and RX lines. These lines are implemented in
hardware and can't be "remapped". The following table shows how the RX and TX
lines are connected to the DB9M:
#1
RX4
(input, commonly DCD)
#2
RX
(input)
#3
TX
(output)
#4
TX3
(output, commonly DTR)
#5
Ground
#6
RX3
(input, commonly DSR)
#7
TX2
(output, commonly RTS)
#8
RX2
(input, commonly CTS)
#9
Each logical serial port of the ser. object also support RTS/CTS flow control, which
is implemented in firmware (TiOS). Ser.rtsmap and ser.ctsmap properties allow you
to assign any GPIO line of the DS1101 to serve as the RTS or CTS line of any logical
serial port. So, TX2 and RX2 lines (pins 7 and 8) can be assigned to work as RTS
and CTS lines, as is traditionally the case for RS232 ports. At the same time, these
lines can be set to function as an independent serial channel.
The same goes for the DTR and DSR lines, except they don't even "exist" from the
ser. object's perspective. These lines are implemented on the application level. For