Interrupt Requests - NEC V850E/IA1 mPD703116 User Manual

10.3.4 Interrupt requests

The following two types of interrupt request are generated from UARTn (n = 1, 2).
•
Reception completion interrupt (INTSRn)
•
Transmission completion interrupt (INTSTn)
The reception completion interrupt has higher default priority than the transmission completion interrupt.
(1) Reception completion interrupt (INTSRn)
In the reception enabled state, the reception completion interrupt (INTSRn) is generated when data in the
reception shift register undergoes shift-in processing and is transferred to the reception buffer.
The reception completion interrupt request (INTSRn) is generated following stop bit sampling. The reception
completion interrupt (INTSRn) is generated upon occurrence of an error.
In the reception disabled state, no reception completion interrupt is generated.
Caution A reception completion interrupt (INTSRn) is generated when the last bit of receive data
(stop bit) is sampled.
(2) Transmission completion interrupt (INTSTn)
Since UARTn does not have a transmission buffer, a transmission completion interrupt request (INTSTn) is
generated when one frame of data containing 7-bit or 8-bit characters or two frames of data containing 9-bit
characters are shifted out from the transmission shift register (TXSn, TXSLn).
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CHAPTER 10 SERIAL INTERFACE FUNCTION
Table 10-5. Default Priority of Generated Interrupts
Interrupt
Reception completion
Transmission completion
User's Manual U14492EJ3V0UD
Priority
1
2