Features; Function Descriptions; Serial Data Format; Figure 174. Uart Serial Data Format - Holtek HT32F50231 User Manual

32-Bit Arm ® Cortex ® -M0+ MCU
HT32F50231/HT32F50241

Features

▄
Supports asynchronous serial communication modes
▄
Full Duplex Communication Capability
▄
Programming baud rate clock frequency up to (f
▄
Fully programmable serial communication functions including:
● Word length: 7, 8 or 9-bit character
● Parity: Even, odd or no-parity bit generation and detection
● Stop bit: 1 or 2 stop bits generation
● Bit order: LSB-first or MSB-first transfer
▄
Error detection: Parity, overrun and frame error

Function Descriptions

Serial Data Format

The UART module performs a parallel-to-serial conversion on data that is written to the transmit
data register and then sends the data with the following format: Start bit, 7 ~ 9 LSB / MSB first
data bits, optional Parity bit and finally 1 ~ 2 Stop bits. The Start bit has the opposite polarity of the
data line idle state. The Stop bit is the same as the data line idle state and provides a delay before
the next start situation. Both the Start and Stop bits are used for data synchronization during the
asynchronous data transmission.
The UART module also performs a serial-to-parallel conversion on the data that is read from the
receive data register. It will first check the Parity bit and will then look for a Stop bit. If the Stop
bit is not found, the UART module will consider the entire word transmission to have failed and
respond with a Framing Error.
Start Bit Bit0
Start Bit Bit0
Start Bit Bit0
Start Bit Bit0
Start Bit Bit0

Figure 174. UART Serial Data Format

Rev. 1.00
7-Bit Data Format
(WLS[1:0]=b00, PBE=0)
Bit1 Bit2 Bit3 Bit4
8-Bit Data Format
(WLS[1:0]=b01, PBE=0)
Bit1 Bit2 Bit3 Bit4
(WLS[1:0]=b00, PBE=1)
Bit1 Bit2 Bit3 Bit4
9-Bit Data Format
(WLS[1:0]=b10, PBE=0)
Bit1 Bit2 Bit3 Bit4
(WLS[1:0]=b01, PBE=1)
Bit1 Bit2 Bit3 Bit4
466 of 486
/16) MHz
PCLK
Next Start
Bit5 Bit6
Stop Bit
Bit
Next Start
Bit5 Bit6 Bit7 Stop Bit
Next Start
Bit5 Bit6 Parity Bit Stop Bit
Bit5 Bit6 Bit7 Bit8
Bit5 Bit6 Bit7 Parity Bit
Bit
Bit
Next Start
Stop Bit
Bit
Next Start
Stop Bit
Bit
July 31, 2018