MCBSTM32EXL Keil, MCBSTM32EXL Datasheet - Page 657

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

Specifications of MCBSTM32EXL

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

RM0008
25.3.1
USART character description
Word length may be selected as being either 8 or 9 bits by programming the M bit in the
USART_CR1 register (see
The TX pin is in low state during the start bit. It is in high state during the stop bit.
An Idle character is interpreted as an entire frame of “1”s followed by the start bit of the next
frame which contains data (The number of “1” ‘s will include the number of stop bits).
A Break character is interpreted on receiving “0”s for a frame period. At the end of the
break frame the transmitter inserts either 1 or 2 stop bits (logic “1” bit) to acknowledge the
start bit.
Transmission and reception are driven by a common baud rate generator, the clock for each
is generated when the enable bit is set respectively for the transmitter and receiver.
The details of each block is given below.
Figure 239. Word length programming
Clock
Clock
9-bit word length (M bit is set), 1 stop bit
Start
bit
8-bit word length (M bit is reset), 1 stop bit
Start
Bit
Universal synchronous asynchronous receiver transmitter (USART)
Bit0
Bit0
Bit1
Bit1
Data frame
Data frame
Idle frame
Break frame
Break frame
Figure
Idle frame
Bit2
Doc ID 13902 Rev 9
Bit2
Bit3
239).
Bit3
Bit4
Bit4
Bit5
Bit5
Bit6
Bit6
Bit7
Possible
Parity
Bit7
Bit
** LBCL bit controls last data clock pulse
****
** LBCL bit controls last data clock pulse
Possible
**
parity
Bit8
bit
Stop
**
Bit
Stop
bit
Stop
Start
Next
Start
bit
Bit
bit
Next
Start
Next data frame
Start
Stop
bit
bit
bit
Start
Next data frame
bit
Start
bit
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