UPD784224 Datasheet, PDF (50/92 Pages) NEC – 16/8-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784224, 784225, 784224Y, 784225Y
8.5 Application Example of Macro Service
(1) Transmission of serial interface
Transfer data storage buffer (memory)
Data n
Data n − 1
Data 2
Data 1
Internal bus
TxD1, TxD2
Transmit shift register TXS1, TXS2 (SFR)
Transfer control
INTST1, INTST2
Each time macro service request INTST1 and INTST2 are generated, the next transmit data is transferred
from memory to TXS1 and TXS2. When data n (last byte) has been transferred to TXS1 and TXS2 (when
the transmit data storage buffer has become empty), vectored interrupt request INTST1 and INTST2 are
generated.
(2) Reception of serial interface
Receive data storage buffer (memory)
Data n
Data n − 1
Data 2
Data 1
Internal bus
RxD1, RxD2
Receive buffer register RXB1, RXB2 (SFR)
Receive shift register
Reception control
INTSR1, INTSR2
Each time macro service request INTSR1 and INTSR2 are generated, the receive data is transferred from
RXB1 and RXB2 to memory. When data n (last byte) has been transferred to memory (when the receive
data storage buffer has become full), vectored interrupt request INTSR1 and INTSR2 are generated.
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Data Sheet U12376EJ1V0DS00