NEC 78K0 User Manual page 300

SI10/P11/R D0
X
f /2
X
2
f /2
X
3
f /2
X
4
f /2
X
5
f /2
X
6
f /2
X
7
f /2
X
SCK10/P10/TxD0
(1) Transmit buffer register 10 (SOTB10)
This register sets the transmit data.
Transmission/reception is started by writing data to SOTB10 when bit 7 (CSIE10) and bit 6 (TRMD10) of serial
operation mode register 10 (CSIM10) are 1.
The data written to SOTB10 is converted from parallel data into serial data by serial I/O shift register 10, and
output to the serial output pin (SO10).
SOTB10 can be written or read by an 8-bit memory manipulation instruction.
RESET input makes this register undefined.
Caution Do not access SOTB10 when CSOT10 = 1 (during serial communication).
(2) Serial I/O shift register 10 (SIO10)
This is an 8-bit register that converts data from parallel data into serial data and vice versa.
This register can be read by an 8-bit memory manipulation instruction.
Reception is started by reading data from SIO10 if bit 6 (TRMD10) of serial operation mode register 10 (CSIM10)
is 0.
During reception, the data is read from the serial input pin (SI10) to SIO10.
RESET input clears this register to 00H.
Caution Do not access SIO10 when CSOT10 = 1 (during serial communication).
300
CHAPTER 14 SERIAL INTERFACE CSI10
Figure 14-1. Block Diagram of Serial Interface CSI10
Internal bus
8
Serial I/O shift Transmit buffer
register 10 (SIO10) register 10 (SOTB10)
Output latch
Transmit data
controller
Transmit controller
Clock start/stop controller &
clock phase controller
User's Manual U16227EJ2V0UD
8
Output
selector
INTCSI10
SO10/P12
Output latch
PM12
(P12)