robotics-university.com | Hello friends, talking about serial communication between microcontroller chip with computer via USB, an embedded system developer need an external device for the bridge of that communication. On today article, I will give an overview about USB To UART (TTL) bridge module. In general, this component used by embedded systems developer or hobbist to make a serial communication with computer.
On this article I explain about USB To UART (TTL) bridge module that use CP2102 chip which manufactured by Silicon Laboratories as the main processor. See figure 1 for the visualization of USB To UART (TTL) bridge (CP2102) and figure 2 for its CP2102 chip example system diagram.
Figure 2. CP2102 - example system diagram
CP2102 Chip Overview & Specifications
Quote from the CP2102 chip datasheet, there mention that the CP2102 is a highly-integrated USB-to-UART Bridge Controller providing a simple solution for updating RS-232 designs to USB using a minimum of components and PCB space. The CP2102 includes a USB 2.0 full-speed function controller, USB transceiver, oscillator, EEPROM, and asynchronous serial data bus (UART) with full modem control signals in a compact 5 x 5 mm MLP-28 package. No other external USB components are required.
The on-chip EEPROM may be used to customize the USB Vendor ID, Product ID, Product Description String, Power Descriptor, Device Release Number, and Device Serial Number as desired for OEM applications. The EEPROM is programmed on-board via the USB allowing the programming step to be easily integrated into the product manufacturing and testing process.
Royalty-free Virtual COM Port (VCP) device drivers provided by Silicon Laboratories allow a CP2102-based product to appear as a COM port to PC applications. The CP2102 UART interface implements all RS-232 signals, including control and handshaking signals, so existing system firmware does not need to be modified. In many existing RS-232 designs, all that is required to update the design from RS-232 to USB is to replace the RS-232 level-translator with the CP2102.
The CP2102 chip has specifications as below:
Single-Chip USB to UART Data Transfer
- Integrated USB transceiver; no external resistors required
- Integrated clock; no external crystal required
- Integrated 1024-Byte EEPROM for vendor ID, product ID, serial number, power descriptor, release number, and product description strings
- On-chip power-on reset circuit
- On-chip voltage regulator: 3.3 V output
- 100% pin and software compatible with CP2101
USB Function Controller
- USB Specification 2.0 compliant; full-speed (12 Mbps)
- USB suspend states supported via SUSPEND pins
Asynchronous Serial Data BUS (UART)
- All handshaking and modem interface signals
- Data formats supported: Data bits (5, 6, 7, and 8), Stop bits (1, 1.5, and 2), Parity (odd, even, mark, space, no parity)
- Baud rates: 300 bps to 1 Mbits
- 576 Byte receive buffer; 640 byte transmit buffer
- Hardware or X-On/X-Off handshaking supported
- Event character support
- Line break transmission
Virtual COM Port Device Drivers
- Works with existing COM Port PC applications
- Royalty-free distribution license
- Windows 98 SE/2000/XP
- MAC OS-9
- MAC OS-X
- Linux 2.40 and greater
- Self-powered: 3.0 to 3.6 V
- USB bus powered: 4.0 to 5.25 V
- Upgrade of RS-232 legacy devices to USB
- Cellular phone USB interface cable
- PDA USB interface cable
- USB to RS-232 serial adapter
USB To UART (TTL) Bridge (CP2102) Module Pins Description
In order you can use this USB To UART (TTL) bridge (CP2102) module, you have to know the pins description, so you can make a true connection between your processor chip with this USB To UART (TTL) bridge (CP2102) module. See figure 3.
Figure 3. USB To UART (TTL) bridge (CP2102) module - pin configuration
From figure 3 above, we know that USB To UART (TTL) bridge (CP2102) module has five pins. They are 3V3 pin, TXD pin, RXD pin, GND pin, and +5V pin. See table 1 for detail pin description.
Table 1. USB To UART (TTL) bridge (CP2102) module - pin description
For detail information about USB To UART (TTL) bridge (CP2102) module, you can download and read its document support from the link which available on the “Source” section of this article.
USB To UART (TTL) Bridge (CP2102) Module Driver
Like another hardware that will interface to computer, in order you can use USB To UART (TTL) bridge (CP2102) module on your computer, you have to install its driver before use it. You can download the driver from Silicon Laboratories official website (www.silabs.com) or by click the third  link on the “Source” section of this article.