Operation In Asynchronous Mode (Operation Modes 0 And 1) - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 21 UART
21.3.1 Operation in Asynchronous Mode (Operation Modes 0
and 1)
Transfer operation becomes asynchronous when the UART is used in Operation Mode
0 (normal mode) or in Operation Mode 1 (multiprocessor mode).
I Operation in asynchronous mode (operation modes 0 and 1)
❍ Transfer data format
Transfer data always starts with a start bit ("L"-level), a transfer operation of a specified bit
length is performed LSB first, and transfer ends with a stop bit ("H"-level).
• In Operation Mode 0, data items without parity are fixed at a length of 7 bits, while data items
with parity have a length of 8 bits.
• In Operation Mode 1, the data length is fixed at 8 bits and a parity bit is not added. Instead,
an A/D (address/data selection bit) is added.
Operation Mode 0
Operation Mode 1
❍ Send Operation
When the transmission data empty flag bit (SSR: TDRE) is "1", send data is written to the output
data register (SODR). The data is sent if send operation is enabled (SCR: TXE = 1) at that time.
Send data is sent to the send shift register and sending starts. The TDRE Flag is then reset to
"1" to enable setting of the next item of send data.
If transmission interrupt requests are enabled (SSR: TIE = 1), a transmission interrupt request is
output to request writing of the send data to the SODR. The TDRE flag is cleared to "0" when
send data has been written to the SODR.
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Figure 21.3-1 Transfer data format (asynchronous mode)
ST D0 D1
ST D0 D1
*1 : D7 (Data bit 7) ..... without parity
*2 : P (Parity bit) ......... with parity
ST : Start bit
SP : Stop bit
A/D : Address/data selection bit in Operation Mode 1 (multiprocessor mode)
D2 D3 D4 D5 D6
D2 D3 D4 D5 D6
*1 *2
D7 /P SP
D7 A/D SP