Starting Uart Reception; Processing At End Of Uart Reception - Mitsubishi Electric M32R Series User Manual

Mitsubishi 32-bit risc single-chip microcomputers

Table of Contents

12.7.2 Starting UART Reception

When all of the following receive conditions are met after you finished initialization, the serial I/O

starts receive operation.

• The SIO Receive Control Register's receive enable bit is set to 1

• Start bit (falling edge signal) is applied to the RXD pin

When the above conditions are met, the serial I/O enters UART receive operation. However, if the

start bit when checked again at the first rise of the internal receive shift clock is detected high for

reason of noise, etc., the serial I/O stops receive operation and waits for the start bit again.

When data reception is completed, the following operation is automatically performed in hardware.

(1) When reception is completed normally

The receive-finished (receive buffer full) bit is set to 1.

Note 1 : If a receive-finished (receive buffer full) interrupt has been enabled, an interrupt request

is generated.

Note 2 : A DMA transfer request is generated.

(2) When error occurs during reception

When an error occurs during reception, the corresponding error bit (OE, FE, or PE) and the

receive sum bit are set to 1.

Note 1 : If a receive-finished interrupt has been selected (by SIO Cause of Receive Interrupt

Select Register), a receive-finished interrupt request is generated when interrupt

requests are enabled. However, if an overrun error has occurred, this interrupt is not

Note 2 : If a receive error interrupt has been selected (by SIO Cause of Receive Interrupt Select

Note 3 : No DMA transfer requests are generated.

12.7 Receive Operation in UART Mode