Setting the MPIE bit to 1 enables the multiprocessor receive interrupt function. In this condition, if
the multiprocessor bit in the receive data is 0, the receive-end interrupt (RXI) and receive-error
interrupt (ERI) are disabled, the receive data is not transferred from RSR to RDR, and the RDRF,
FER, PER, and ORER bits in the serial status register (SSR) are not set. If the multiprocessor bit is
1, however, the MPB bit in SSR is set to 1, the MPIE bit is cleared to 0, the receive data is
transferred from RSR to RDR, the FER, PER, and ORER bits can be set, and the receive-end and
receive-error interrupts are enabled.
Bit 3: MPIE
Description
0
The multiprocessor receive interrupt function is disabled.
(Normal receive operation)
(Initial value)
1
The multiprocessor receive interrupt function is enabled. During the interval
before data with the multiprocessor bit set to 1 is received, the receive interrupt
request (RXI) and receive-error interrupt request (ERI) are disabled, the RDRF,
FER, PER, and ORER bits are not set in the serial status register (SSR), and
no data is transferred from the RSR to the RDR. The MPIE bit is cleared at the
following times:
1. When 0 is written in MPIE.
2. When data with the multiprocessor bit set to 1 is received.
Bit 2—Transmit-End Interrupt Enable (TEIE): This bit enables or disables the TSR-empty
interrupt (TEI) requested when the transmit-end bit (TEND) in the serial status register (SSR) is
set to 1.
Bit 2: TEIE
Description
0
1
The TSR-empty interrupt request (TEI) is disabled.
The TSR-empty interrupt request (TEI) is enabled.
(Initial value)
Bit 1—Clock Enable 1 (CKE1): This bit selects the internal or external clock source for the baud
rate generator. When the external clock source is selected, the SCK pin is automatically used for
input of the external clock signal.
Bit 1: CKE1
Description
0
Internal clock source
(Initial value)
When C/A = 1, the serial clock signal is output at the SCK pin.
When C/A = 0, output depends on the CKE0 bit.
External clock source. The SCK pin is used for input.
1
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HITACHI [ HITACHI SEMICONDUCTOR ]
