CP2104-EK
Rev. 0.7
5
6.3. UART Signals (P2, J1)
An RS232 transceiver circuit and DB9 connector (P2) are provided on the evaluation board to connect the CP2104
virtual serial port to external serial devices. See Table 3 for the RS232 P2 pin descriptions. The J1 connector is
provided to facilitate direct access to the CP2104’s UART signals. Shorting blocks on J1 are required to connect
the UART signals to P2. See Table 4 for J1 pin descriptions.
6.4. Power Connector (J4)
This header (J4) is included on the evaluation board to provide several power options. The following describes the
function of each pin:
Pins 1–2: Connects CP2104 VIO input (Pin 5) to CP2104 VDD (Pin 6). Remove the shorting block to power
VIO from an external source.
Pins 3–4: Connects the main +3 V net to the CP2104 VDD (Pin 6). The main +3 V net powers the other
components (four green LEDs and RS232 Sipex Part) on the evaluation board.
Table 3. RS232 Pin Descriptions
Pin
Signal
CP2104
Direction
Description
1
DCD
Input
Data Carrier Detect
2
RXD
Input
Receive Data
3
TXD
Output
Transmit Data
4
DTR
Output
Data Terminal Ready
5
GND
Ground
6
DSR
Input
Data Set Ready
7
RTS
Output
Request to Send
8
CTS
Input
Clear to Send
9
RI
Input
Ring Indicator
Table 4. J1 Pin Descriptions
Pins
Signal
CP2104
Direction
Description
1–2
TXD
Output
Transmit Data
3–4
RXD
Input
Receive Data
5–6
DTR
Output
Data Terminal Ready
7–8
RI
Input
Ring Indicator
9–10
DCD
Input
Data Carrier Detect
11–12
DSR
Input
Data Set Ready
13–14
CTS
Input
Clear to Send
15–16
RTS
Output
Request to Send
