Hardware Description
7
SLLU250 – November 2016
Copyright © 2016, Texas Instruments Incorporated
BOOSTXL-RS232 BoosterPack™ Hardware
3.4
DB9 Connector
The BoosterPack includes a female data circuit-terminating equipment (DCE) DB9 port. Female DCE
ports are designed to connect with the male data terminal equipment (DTE) port of the computer. The
labeling for
is from the perspective of the computer with the DTE port. Therefore, RX1 is actually
an output from the BoosterPack to the connected device through the RS232 interface, while TX1 is an
input from the connected device to the BoosterPack through the RS232 interface. The same applies to the
RTS1 (input) and CTS1 (output) ports. The RX2, TX2, CTS2, and RTS2 ports are used to interface with
the microcontroller through 0-V to 3.3-V (or 1.8-V) TTL signals. See
for information on how the
DB9 connector is routed on the BOOSTXL-RS232 BoosterPack.
Figure 6. DB9 Pinout
Table 1. RS-232 Female DB9 Connector Pin Summary
Pin
Function
1
NC
2
UART Receive 1 (RX1)
3
UART Transmit 1 (TX1)
4
Shorted to pin 6 (unused flow control line)
5
GND
6
Shorted to pin 4 (unused flow control line)
7
Request to Send 1 (RTS1)
8
Clear to Send 1 (CTS1)
9
NC
