Datasheet

78K0/Ix2 CHAPTER 16 SERIAL INTERFACE CSI11
R01UH0010EJ0500 Rev.5.00 562
Feb 28, 2012
(3) Timing of output to SO11 pin (first bit)
When communication is started, the value of transmit buffer register 11 (SOTB11) is output from the SO11 pin. The
output operation of the first bit at this time is described below.
Figure 16-8. Output Operation of First Bit (1/2)
(a) Type 1: CKP11 = 0, DAP11 = 0
SCK11
SOTB11
SIO11
SO11
Writing to SOTB11 or
reading from SIO11
First bit 2nd bit
Output latch
(b) Type 3: CKP11 = 1, DAP11 = 0
SCK11
SOTB11
SIO11
Output latch
SO11
Writing to SOTB11 or
reading from SIO11
First bit 2nd bit
The first bit is directly latched by the SOTB11 register to the output latch at the falling (or rising) edge of SCK11, and
output from the SO11 pin via an output selector. Then, the value of the SOTB11 register is transferred to the SIO11
register at the next rising (or falling) edge of SCK11, and shifted one bit. At the same time, the first bit of the receive
data is stored in the SIO11 register via the SI11 pin.
The second and subsequent bits are latched by the SIO11 register to the output latch at the next falling (or rising)
edge of SCK11, and the data is output from the SO11 pin.