CP2105EK Silicon Laboratories Inc, CP2105EK Datasheet - Page 16

• Manufacturer Part Number: CP2105EK
• Description: KIT EVAL FOR CP2105
• Manufacturer: Silicon Laboratories Inc

Specifications of CP2105EK

• Main Purpose: Interface, Dual USB 2.0 to UART (RS485) Bridge
• Embedded: No
• Utilized Ic / Part: CP2105
• Primary Attributes: Full Speed (12Mbps)
• Secondary Attributes: LED Status Indicators
• Interface Type: RS-232, USB
• Operating Supply Voltage: 3.3 V
• Product: Interface Development Tools
• For Use With/related Products: CP2105
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 336-2005

CP2105
8.3. Hardware Flow Control (RTS and CTS)
To utilize the functionality of the RTS and CTS pins of the CP2105, the device must be configured to use hardware
flow control.
RTS, or Ready To Send, is an active-low output from the CP2105 and indicates to the external UART device that
the CP2105’s UART RX FIFO has not reached the watermark level of 191 bytes on the Enhanced Communication
interface or 63 bytes on the Standard Communication Interface and is ready to accept more data. When the
amount of data in the RX FIFO reaches the watermark, the CP2105 pulls RTS high to indicate to the external
UART device to stop sending data.
CTS, or Clear To Send, is an active-low input to the CP2105 and is used by the external UART device to indicate to
the CP2105 when the external UART device’s RX FIFO is getting full. The CP2105 will not send more than two
bytes of data once CTS is pulled high.
16
Figure 7. Hardware Flow Control Typical Connection Diagram
CP2105
RTS
CTS
RX
TX
Rev. 1.0
TX
RX
RTS
CTS
System
RS232