Figure 10.3.2 Serial 1 Data Register (Sdr1) - Fujitsu F2MC-8L MB89620 Series Hardware Manual

10.3 Structure of 8-bit Serial I/O-1
10.3.2 Serial 1 Data Register (SDR1)
The serial 1 data register (SDR1) stores the transfer data for 8-bit serial I/O-1.
The register functions as the transmit data register for serial output operation and as
the receive data register for serial input operation.
n Serial 1 Data Register (SDR1)
Figure 10.3.2 shows the bit structure of the serial 1 data register.
Register Address
SDR1
R/W: Readable and writable
X : Indeterminate
Serial output operation
l
The register functions as the transmit data register. When serial I/O transfer starts (SMR1: SST
= "1"), the 8-bit serial I/O performs serial transfer of the data written in the register.
Serial input operation
l
The register functions as the receive data register. When serial I/O transfer starts (SMR1: SST
= "1"), the received serial transfer data is stored in this register.
During serial I/O transfer
l
Do not write a data to the SDR1 register during serial I/O transfer operating. Also, the read
value has no meaning.
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CHAPTER 10 8-BIT SERIAL I/O (SERIAL I/O-1 AND SERIAL I/O-2)
Bit 7 Bit 6
001D
H
R/W R/W

Figure 10.3.2 Serial 1 Data Register (SDR1)

Bit 5 Bit 4 Bit 3 Bit 2
R/W R/W R/W R/W
Bit 1 Bit 0 Initial value
XXXXXXXX
R/W R/W
MB89620 series
B