MCBSTM32EXL Keil, MCBSTM32EXL Datasheet - Page 681

• Manufacturer Part Number: MCBSTM32EXL
• Description: BOARD EVALUATION FOR STM32F103ZE
• Manufacturer: Keil

Specifications of MCBSTM32EXL

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

RM0008
25.4
CTS flow control
If the CTS flow control is enabled (CTSE=1), then the transmitter checks the nCTS input
before transmitting the next frame. If nCTS is asserted (tied low), then the next data is
transmitted (assuming that a data is to be transmitted, in other words, if TXE=0), else the
transmission does not occur. When nCTS is deasserted during a transmission, the current
transmission is completed before the transmitter stops.
When CTSE=1, the CTSIF status bit is automatically set by hardware as soon as the nCTS
input toggles. It indicates when the receiver becomes ready or not ready for communication.
An interrupt is generated if the CTSIE bit in the USART_CR3 register is set. The figure
below shows an example of communication with CTS flow control enabled.
Figure 258. CTS flow control
USART interrupts
Table 178. USART interrupt requests
Transmit Data Register Empty
CTS flag
Transmission Complete
Received Data Ready to be Read
Overrun Error Detected
Idle Line Detected
Parity Error
Break Flag
Noise Flag, Overrun error and Framing Error in multibuffer
communication
nCTS
Transmit data register
TDR
TX
Data 1
Data 2
Stop
Bit
Writing data 3 in TDR
Universal synchronous asynchronous receiver transmitter (USART)
Start
Bit
Interrupt event
empty
Doc ID 13902 Rev 9
Data 2
is delayed until nCTS = 0
Transmission of Data 3
CTS
Data 3
Stop
Bit
Idle Start
Bit
TC
RXNE
ORE
PE
LBD
NE or ORE or FE EIE
TXE
CTS
IDLE
CTS
Event flag
empty
Data 3
TXEIE
CTSIE
TCIE
RXNEIE
IDLEIE
PEIE
LBDIE
Control bit
Enable
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