274
User’s Manual U15798EJ2V0UD
CHAPTER 15 SERIAL INTERFACE CSI1
Figure 15-1. Block Diagram of Serial Interface CSI1
(1) Transmit buffer register 1 (SOTB1)
This register sets transmit data.
Transmission/reception is started by writing data to SOTB1 when bit 6 (TRMD1) of serial operation mode register
1 (CSIM1) is 1.
The data written to SOTB1 is converted from parallel data into serial data by serial I/O shift register 1, and output
to the serial output (SO1) pin.
SOTB1 can be written or read by an 8-bit memory manipulation instruction.
RESET input makes the value of this register undefined.
Caution Do not access SOTB1 when CSOT1 = 1 (during serial communication).
(2) Serial I/O shift register 1 (SIO1)
This is an 8-bit register that converts data from parallel into serial or vice versa.
Reception is started by reading data from SIO1 if bit 6 (TRMD1) of serial operation mode register 1 (CSIM1) is
0.
During reception, the data is read from the serial input pin (SI1) to SIO1.
This register can be read by an 8-bit memory manipulation instruction.
RESET input makes the value of this register undefined.
Caution Do not access SIO1 when CSOT1 = 1 (during serial communication).
8
8
SO1/P24
INTCSI1
SI1/P23
Output
selector
f
X
/2
2
to f
X
/2
8
SCK1/P25
Internal bus
Serial I/O shift
register 1 (SIO1)
Transmit buffer
register 1 (SOTB1)
Output latch
Transmit controller
Clock start/stop controller
& clock phase controller
Selector
Transmit data
controller
Содержание mPD780344 Series
Страница 2: ...2 User s Manual U15798EJ2V0UD MEMO...