CP2104EK Silicon Laboratories Inc, CP2104EK Datasheet - Page 14

• Manufacturer Part Number: CP2104EK
• Description: KIT EVAL FOR CP2104
• Manufacturer: Silicon Laboratories Inc

Specifications of CP2104EK

• Main Purpose: Interface, USB 2.0 to UART (RS485) Bridge
• Embedded: No
• Utilized Ic / Part: CP2104
• 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: CP2104
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 336-2007

CP2104
7.3. Hardware Flow Control (RTS and CTS)
To utilize the functionality of the RTS and CTS pins of the CP2104, the device must be configured to use hardware
flow control.
RTS, or Ready To Send, is an active-low output from the CP2104 and indicates to the external UART device that
the CP2104’s UART RX FIFO has not reached the watermark level of 383 bytes and is ready to accept more data.
When the amount of data in the RX FIFO reaches the watermark, the CP2104 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 CP2104 and is used by the external UART device to indicate to
the CP2104 when the external UART device’s RX FIFO is getting full. The CP2104 will not send more than two
bytes of data once CTS is pulled high.
14
Figure 7. Hardware Flow Control Typical Connection Diagram
CP2104
RTS
CTS
RX
TX
Rev. 1.0
TX
RX
RTS
CTS
System
RS232