SILICON LAB CP2108-EK CP2108 Evaluation Kit User Guide
- June 13, 2024
- SILICON LAB
Table of Contents
SILICON LAB CP2108-EK CP2108 Evaluation Kit User Guide
Kit Contents
The CP2108 Evaluation Kit contains the following items:
- CP2108 evaluation board
- Four RS232 serial cables
- USB cable
- Quick Start Guide
Relevant Documentation
Application notes are available 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 CP2108 EEPROM.
- 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 CP2108 GPIO pins.
- AN571: CP210x Virtual COM Port Interface — USB interface details for CP210x devices.
Software Setup
The software packages and documentation for the CP2108 kit are available on the device page (https://www.silabs.com/interface/usb- bridges/classic/device.cp2108) and include the following
- CP210x Drivers (Software & Tools Tab)
- USBXpress Host SDK (Software & Tools Tab)
- Documentation: (Tech Docs Tab)
- CP2108 data sheet
- CP2108 Evaluation Kit User’s Guide (this document)
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, and a 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:\Silicon Labs\MCU\USBXpress_SDK.
Further installation instructions for the WinCE drivers are available in the ReadMe.txt file contained inside the driver package.
CP2108 Hardware Interface
Connect the CP2108 evaluation board to a PC as shown in Figure 1.
Figure 1. Hardware Setup
- 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 CP2108 evaluation board.
- Connect one end of the RS232 serial cable to one of the DB9 connectors on the CP2108 evaluation board.
- Connect the other end of the RS232 serial cable to the target serial device.
- To connect to additional serial devices, repeat Steps 3 and 4 using another RS232 serial cable and one of the unused DB9 connectors on the CP2108 evaluation board.
CP2108 Software Interface
If the Virtual COM Port drivers are used, the CP2108 will appear as four COM
ports in the Device Manager, as shown in Figure 2. The CP2108 will always use
the lowest available COM ports for operation. For instance, if COM ports 1
through 6 are in use by other peripherals and applications, the CP2108 will
use COM 7, COM 8, COM 9 and COM 10.
Figure 2. CP210x in Device Manager Using the VCP Driver
The CP2108 functions identically to four COM ports from the reference point of both the host application and the serial devices, and it can support serial device control requests defined in the Microsoft Win32® Communications API. Examples for how to communicate with the device as two serial COM ports are included in application note, “AN197: Serial Communications for the CP210x” on the www.silabs.com/interface-appnotes page or in the USBXpress Host SDK.
If the USBXpress drivers are used, the CP2108 will appear as four USB
USBXpress devices as shown in Figure 3. The USBXpress driver must be
customized using application note, “AN220: USB Driver Customization”. Examples
for how to communicate with the device using the USBXpress interface are
included in application note, “AN169: USBXpress Programmer’s Guide”, on the
www.silabs.com/interface-appnotes
page.
Figure 3. CP210x in Device Manager Using the USBXpress Driver
Target Board
The CP2108 Evaluation Kit includes an evaluation board with a CP2108 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 4 for the locations of the various I/O
connectors.
Figure 4. CP2108 Evaluation Board with Default Shorting Blocks Installed
P0-3: DB9 connectors for the RS232 interface
P4: USB connector for USB interface
J0-3: UART signal access connector
J4: SUSPEND LED connector
DS8: Red SUSPEND indicator LED
J5: Board Power Selector (bus- or self-powered)
J6: GPIO0-7 LED Connector
J7: GPIO8-15 Rx/Tx Toggle Pins
J8: VBUS Pin Connection for current measurements
J9: +3V/VDD Connector Option
J10: VIO/VDD Connector Option
J11: NC Pins, GND
DS0-DS7: Green GPIO LEDs
DB9 Connector for RS232 Interface (P0-P3, J0-J3)
Four RS232 transceiver circuits and DB9 connectors (P0-3) are provided on the
evaluation board to connect the CP2108 virtual serial ports to external serial
devices. The headers J0-3 connect the CP2108 pins to the DB9 connectors and
provide access to the RS232 signals. See Table 1 for the RS232 P0-3 pin
descriptions and Table 2 for J0, J1, J2, J3 pin descriptions.
Table 1. RS232 Connector (P0-3) Pin Descriptions
| Pin | Signal | CP2108 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 2. RS232 Header (J0-3) Pin Descriptions
| Pins | Signal | CP2108 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 |
Board Power Selector (J5)
This header (J5) provides bus- or self-powered options for the CP2108 device.
- Pins 1-2 connect USB connector VBUS (P4) to the VREGIN pin on the CP2108 and puts the device in bus powered mode. The voltage regulator output appears on the VDD pin (pin 3).
- Pins 2-3 connect the CP2108 VREGIN to the CP2108 VDD pin and puts the device in self-powered mode.
This bypasses the voltage regulator. A voltage of 1.8 to 3.6 V power must be supplied to the VDD pin.
Power Connectors (J9, J10)
The J9 and J10 headers are included on the evaluation board to provide several
power options.
-
J9 connects the main +3 V net to the CP2108 VDD pin. The VDD pin is the output of the on-chip regulator.
The main +3 V net powers the other components (green LEDs and RS-232 transceivers) on the board. It can be disconnected using J9 for current measurement purposes. -
J10 connects the CP2108 VIO input to the CP2108 VDD pin. Remove the shorting block to power VIO from an external source.
VBUS Connector (J8)
The VBUS connector J8 connects the VBUS pin on the USB connector (P4) to the
CP2108 VBUS pin. If the jumper is removed and a multimeter is inserted, the
power consumption can be measured.
GPIO.0-7 LED Header (J6)
Place shorting blocks on J6 to connect the GPIO.0–7 pins to the eight green
LEDs (DS0-DS7). These LEDs can be used to indicate active communications
through the CP2108. Table 3 shows the LED corresponding to each header
position. When using the CP2108 in modem mode, the shorting blocks on J6
should be removed.
Table 3. J6 LED Locations
| LED | J6 Pins |
|---|---|
| DS0 | 1-2 |
| DS1 | 3-4 |
| DS2 | 5-6 |
| DS3 | 7-8 |
| DS4 | 9-10 |
| DS5 | 11-12 |
| DS6 | 13-14 |
| DS7 | 15-16 |
GPIO.8-15 Header (J7)
The J7 header allows access to the GPIO.8-15 pins on the CP2108. These GPIO
pins may be connected to the LEDs using J6 or used for alternate functions
described in the CP2108 data sheet.
Universal Serial Bus (USB) Interface (P4)
A Universal Serial Bus (USB) connector (P4) is provided to facilitate
connections to the USB interface on the CP2108. See Table 4 for the USB pin
definitions.
Table 4. USB Connector Pin Descriptions
| Pin # | Description |
|---|---|
| 1 | VBUS |
| 2 | D- |
| 3 | D+ |
| 4 | GND (Ground) |
SUSPEND LED Header (J4)
The J4 header enables the DS8 LED on the SUSPEND output pin on the CP2108.
Schematic
Figure 5. CP2108 Evaluation Kit Board Schematic
**Rev. 0.3 9 Figure 6. CP2108 Evaluation Kit Board Schematic
**
DOCUMENT CHANGE LIST
Revision 0.2 to Revision 0.3
- Removed section “1. Introduction”.
- Added section “2. Relevant Documentation”.
- Updated section “3. Software Setup” to point to new hyperlink for the drivers on the website.
- Added section “3.1. USBXpress Driver Development Kit”
- Updated section “5. CP2108 Software Interface”
- Added “Figure 3: CP210x in Device Manager Using the USBXpress Driver”
- Changed section “6. Detailed Hardware Description” to “6.Target Board”
References
- Technical Resource Search - Silicon Labs
- Interface Direct Access Drivers - Silicon Labs
- CP2108 Classic USB to UART Bridge - Silicon Labs