Notes On Using Uart - Fujitsu F2MC-16LX Hardware Manual

21.8

Notes on Using UART

Use of the UART requires the following cautions.
Notes on Using UART
Enabling sending and receiving
• The bits indicating that sending operation is enabled (SCR0 to SCR3: TXE) and that receiving operation
is enabled (SCR0 to SCR3: RXE) is provided for sending and receiving respectively.
• In the initial state after a reset, transmission and reception are both disabled (SCR0 to
SCR3:TXE=0,RXE=0). Transmission and reception must therefore be enabled in advance.
• The device can stop transmission and reception by disabling them (SCR0 to SCR3:TXE=0,RXE=0).
Setting operation mode
Set the operation mode after disabling transmission and reception (SCR0 to SCR3:TXE=0,RXE=0). When
the operation mode is changed during transmission or reception, the transmitted/received data is not
guaranteed.
About clock synchronous mode
Operation mode 2 is set as a clock synchronizer method. Transmit/receive data is associated with no start
and stop bits.
Transmission interrupt enable timing
The sending data empty flag bit (SSR0 to SSR3: TDRE) is set to "1" (no sending data, enabled to write
sending data) by default after resetting. So, as soon as a sending interrupt is enabled (SSR0 to SSR3:
TIE=1), the sending interrupt request is generated. Be sure to prepare data to transmit before enabling
transmission (SSR0 to SSR3:TIE=1).
Receiving Multiprocessor mode
In the multiprocessor mode, receiving operation based on 9-bit receipt is not allowed.
CHAPTER 21 UART
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