CP2104-EK
CP2104 E VALUATION K IT U SER ’ S G UIDE
1. Kit Contents
The CP2104 Evaluation Kit contains the following items:
CP2104
Evaluation Board
RS232 Serial Cable
USB Cable
Quick Start Guide
2. Relevant Documentation
Application notes can be found on the Interface Application Notes page for all fixed-function devices:
www.silabs.com/interface-appnotes.
AN721:
USBXpress™ Device Configuration and Programming Guide — Customize the VID, PID,
serial number, and other parameters stored in the CP2104 one-time programmable ROM.
AN197: Serial Communications Guide for CP210x — Programming guide for using the Virtual COM Port
(VCP) drivers.
AN169: USBXpress® Programmer's Guide — Programming guide for using the USBXpress drivers.
AN220: USB Driver Customization — VCP or USBXpress driver customization tool.
AN223: Runtime GPIO Control for CP210x — Programming guide and DLL for runtime control of the
CP2104 GPIO pins.
AN571: CP210x Virtual COM Port Interface — USB interface details for CP210x devices.
3. Software Setup
The software packages and documentation for the CP2104 kit can be found on the device page (https://
www.silabs.com/interface/usb-bridges/classic/device.cp2104) and include the following:
CP210x
Drivers (Software & Tools Tab)
Host SDK (Software & Tools Tab)
Documentation: (Tech Docs Tab)
USBXpress
CP2104
CP2104
data sheet
evaluation kit user's guide (this document)
3.1. USBXpress Driver Development Kit
The Silicon Laboratories USBXpress® Development Kit provides a complete host software solution for interfacing to
CP210x devices. No USB protocol or host device driver expertise is required. Instead, a simple, high-level Application
Program Interface (API) for the host software is used to provide complete USB connectivity. The USBXpress
Development Kit includes Windows device drivers, Windows device driver installer, host interface function library
(host API) provided in the form of a Windows Dynamic Link Library (DLL). See Application Note AN169,
“USBXpress® Programmer's Guide” for detailed information on using the USBXpress drivers.
The USBXpress drivers are available here: https://www.silabs.com/developers/direct-access-drivers.
Click the USBXpress Development Kit link in the Downloads section to download the USBXpress drivers. Run the
installer and follow the steps to install the software to the desired location. The default installation directory is
C:\SiliconLabs\MCU\USBXpress_SDK.
Further installation instructions for the WinCE drivers can be found in the ReadMe.txt file contained inside the
driver package.
Rev. 0.8 1/21
Copyright © 2021 by Silicon Laboratories
CP2104-EK
CP2104-EK
4. CP2104 Hardware Interface
The evaluation board is connected to a PC as shown in Figure 1.
1.
2.
3.
4.
Connect one end of the USB cable to a USB Port on the PC.
Connect the other end of the USB cable to the USB connector on the CP2104 evaluation board.
Connect one end of the RS232 serial cable to the DB-9 connector on the CP2104 evaluation board.
Connect the other end of the RS232 serial cable to the target serial device.
1
2
USB
RS232
CP2104 USB-toUART Bridge
4
Serial Device
3
CP2104 EK
Figure 1. Hardware Setup
2
Rev. 0.8
CP2104-EK
5. CP2104 Software Interface
If the Virtual COM Port drivers are used, the CP2104 will appear as a COM port in the Device Manager, as shown
in Figure 2. The CP2104 will always use the lowest available COM port for operation. For instance, if COM ports 1
and 2 are in use by other peripherals and applications, the CP2104 will use COM 3.
The CP2104 functions identically to a COM port from the reference point of both the host application and the serial
device, and it can support serial device control requests defined in the Microsoft Win32® Communications API.
Examples for how to communicate with the device as a serial COM port are included in AN197 on the
www.silabs.com/interface-appnotes page or in the USBXpress Host SDK.
If the USBXpress drivers are used, the CP2104 will appear as a USB USBXpress device as shown in Figure 2.
Examples for how to communicate with the device using the USBXpress interface are included in AN169 on the
www.silabs.com/interface-appnotes page.
Figure 2. CP2104 in Device Manager
Rev. 0.8
3
CP2104-EK
6. Target Board
The CP2104 Evaluation Kit includes an evaluation board with a CP2104 device pre-installed for evaluation and preliminary software development. Numerous input/output (I/O) connections are provided to facilitate prototyping using
the evaluation board. Refer to Figure 3 for the locations of the various I/O connectors.
P1
P2
J1
J2,
J3
J4
DS0–DS3
DS4
USB connector for USB interface
DB9 connector for RS232 interface
UART signal access connector
GPIO access connector
Power connector
Green GPIO LEDs
Red SUSPEND indicator LED
_________
SUSPEND LED
DS4
P2
J2
RS232
Transceiver
P1
CP2104
Pin 1
Pin 2
DS3
DS2
J1
J3
J4
DS1
DS0
Figure 3. CP2104 Evaluation Board with Default Shorting Blocks Installed
6.1. LED Headers (J2, J3)
Connectors J2 and J3 are provided to allow access to the GPIO pins on the CP2104. Place shorting blocks on J2
and J3 to connect the GPIO pins to the four green LEDs DS0–DS3. These LEDs can be used to indicate active
communications through the CP2104. Table 1 shows the LED corresponding to each header position.
Table 1. J2 and J3 LED Locations
LED
Pins
DS0
J3[3:4]
DS1
J3[1:2]
DS2
J2[3:4]
DS3
J2[1:2]
6.2. Universal Serial Bus (USB) Interface (P1)
A Universal Serial Bus (USB) connector (P1) is provided to facilitate connections to the USB interface on the
CP2104. See Table 2 for the USB pin definitions.
Table 2. USB Connector Pin Descriptions
4
Pin #
Description
1
VBUS
2
D-
3
D+
4
GND (Ground)
Rev. 0.8
CP2104-EK
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.
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
6
DSR
Input
Data Set Ready
7
RTS
Output
Request to Send
8
CTS
Input
Clear to Send
9
RI
Input
Ring Indicator
Ground
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
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.
Rev. 0.8
5
Figure 4. CP2104 Evaluation Board Schematic
CP2104-EK
7. Schematic
6
Rev. 0.8
CP2104-EK
DOCUMENT CHANGE LIST
Revision 0.1 to Revision 0.2
Updated "6.4. Power Connector (J4)" on page 5 to
reflect the updated schematic.
Updated J4 in Figure 4, “CP2104 Evaluation Board
Schematic,” on page 6.
Revision 0.2 to Revision 0.3
Updated "7. Schematic" on page 6.
Revision 0.3 to Revision 0.4
Updated "2.1.1. Virtual COM Port Driver Installation
for Windows" on page 1.
Updated "2.2.1. USBXpress Installation for
Windows" on page 2.
Removed “2.2.2. USBXpress Installation for
Windows 98SE” on page 2.
Revision 0.4 to Revision 0.5
Updated Figure 3 with shorting blocks installed.
Revision 0.5 to Revision 0.6
Updated "3. Software Setup" on page 1.
Revision 0.6 to Revision 0.7
Updated “1. Kit Contents” to change CD-ROM to
DVD.
Added “2. Relevant Documentation”.
Updated “3. Software Setup” to point to the drivers
on the website.
Updated Figure 1 and Figure 2.
Revision 0.7 to Revision 0.8
Updated "Kit Contents" on page 1 to remove DVD.
Updated "Relevant Documentation" on page 1.
Updated "Software Setup" on page 1.
Rev. 0.8
7
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Disclaimer
Silicon Labs intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using or
intending to use the Silicon Labs products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific device, and “Typical”
parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only. Silicon Labs reserves the right to make changes
without further notice to the product information, specifications, and descriptions herein, and does not give warranties as to the accuracy or completeness of the included information.
Without prior notification, Silicon Labs may update product firmware during the manufacturing process for security or reliability reasons. Such changes will not alter the specifications or
the performance of the product. Silicon Labs shall have no liability for the consequences of use of the information supplied in this document. This document does not imply or expressly
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