Chapter 3 Hardware
CoreModule 420 Reference Manual 35
Pin # Signal DB9 # Description
4RTS* 7
Request To Send – Indicates serial port is ready to transmit data. Used
as hardware handshake with CTS for l o w level flow control.
5 TXD 3 Transmit Data – Serial port transmit data output is typically held to a
logic 1 when no data is being sent. T ypi cally, a logic 0 (On) must be
present on RTS, CTS, DSR, and DTR before data can be transmitted on
this line.
6CTS* 8
Clear To Send – Indicator to serial port that external serial
communications device is ready to receive data. Used as hardware
handshake with RTS for low level flo w control.
7DTR* 4
Data Terminal Ready – Indicates serial port is powered, initialized, and
ready. Used as hardware handshake with DSR for overall readiness to
communicate.
8RI* 9
Ring Indicator – Indicator to serial port that external modem is detecting
a ring condition. Used by software to initiate operations to answer and
open the communications channel.
9GND 5 Digital Ground
10 Key/NC NC Key Pin – Not connected
Notes: The shaded area denotes power or ground. The signals marked with * indicate active low.
USB Port (J10)The CoreModule 420 contains one root USB (Universal Serial Bus) hub and one functional USB port.
The USB function is provided by the STPC ATLAS CPU (U14). Features implemented in the USB port
include the following:
•One root hub with one USB port
•USB v.1.1 and Universal OHCI v.1.0 compatible
•Over-current detection status is provided by STPC ATLAS CPU (pin D21)
•Supports a fuse (F1, 1.5A) for over current protection
Table 3-14. USB Interface Pin and Signal Designations (J10)
Pin # Signal Description
1 USBPWR USB Power – Vcc power (+/-5%) to port through fuse. Port is
disabled if this input is low.
2 USBPN USB Port Data Negative.
3 USBPP USB Port Data Positive
4GND USB P ort ground
5 SHIELD USB Port shield
Notes: The shaded area denotes power or ground.