Specifications

Digi m10 Hardware Reference v 1.20
Digi International, Inc. © 2013
Page 12 of 38
2.2 Serial Interface
2.2.1 Host Port
The host port is the main serial interface and provides device management and monitoring using
3.3 V levels. The serial data is carried on the Transmit (TX) and Receive (RX) lines. The details of
the Transmit and Receive pins are shown in Table 2. An RS232 level shifter is required to
connect the Digi m10 to a PC. This is already available on the development board, which comes
with the Digi m10 JumpStart Kit.
Table 2: Host Transmit and Receive Pins
Pin
Name
Description
8
TX
3.3 V UART interface;
Digi m10 to the host
controller
7
RX
3.3 V UART interface;
host controller to the
Digi m10
Note: The RX line (Pin 7) needs to be pulled high using a 10KΩ resistor to 3.3V on the Host
board.
2.2.2 Host Port (With Flow Control)
Hardware flow control is implemented using RTS (Request to Send) and CTS (Clear To Send)
signals.
Assertion is set to 0V and De-Assertion is set to 3.3V. At power up RTS is configured as
input, CTS is configured as output and is set to asserted state. When flow control is enabled via
extended packet by DTE, RTS serves as input to m10 and is controlled by DTE where as CTS is
input to DTE and is controlled by m10.When M10 is ready to receive data from DTE, it asserts the
CTS line. Similarly, when DTE is ready to receive data from M10, it should assert the RTS line.
2.2.3 Debug Port
The Digi m10’s diagnostics (this is an optional interface) can be accessed through this port using
a terminal emulation program at 115200 baud rate.
Table 3: Debug Transmit and Receive Pins
Pin
Name
Description
11
Dbg_Tx
3.3 V UART debug
interface; Digi m10 to
the host controller
12 Dbg_Rx 3.3 V UART debug
interface; host controller