7643_06 Datasheet, PDF (152/424 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER

7643 Group
APPLICATION
2.3 Serial I/O
When the registers are set as shown in Figure 2.3.13, the serial I/O can transmit 1-byte data by
writing data into the serial I/O shift register.
Thus, after setting the CS signal to “L”, write the transmission data to the serial I/O shift register
by each 1 byte, and return the CS signal to “H” when all required data have been transmitted.
Figure 2.3.13 shows a control procedure of transmitter.
RESET
Initialization
SIOCON1 (Address : 2B16) 010011002
SIOCON2 (Address : 2C16) 000111002
P3
(Address : 0E16), bit1 1
P3D
(Address : 0F16), bit1 1
IREQC (Address : 0416), bit3 0
ICONC (Address : 0716), bit3 0
CLI
q x: This bit is not used here. Set it to “0” or “1” arbitrarily.
•Serial I/O set
•CS signal output port set
(“H” level output)
•Serial I/O interrupt request bit set to “0”
•Serial I/O interrupt disabled
P3 (Address : 0E16), bit1
0
•CS signal output level to “L” set
SIOSHT (Address : 2A16)
Transmi-
ssion data
•Transmission data write
(Start of transmit 1-byte data)
0
IREQC (Address : 0416), bit3?
1
IREQC (Address : 0416), bit3 0
•Judgment of completion of transmitting
1-byte data
N
Complete to transmit all data?
Y
P3 (Address : 0E16), bit1 1
•Use any of RAM area as a counter for counting
the number of transmitted bytes
•Judgment of completion of transmitting all data
•Return the CS signal output level to “H”
when transmission of all data is completed
Fig. 2.3.13 Control procedure of transmitter
Rev.2.00 Aug 28, 2006 page 31 of 202
REJ09B0133-0200