upd78f0124hgba1-8et-a Renesas Electronics Corporation., upd78f0124hgba1-8et-a Datasheet - Page 317

• Manufacturer Part Number: upd78f0124hgba1-8et-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(3) Timing of output to SO10 pin (first bit)
When communication is started, the value of transmit buffer register 10 (SOTB10) is output from the SO10 pin.
The output operation of the first bit at this time is described below.
The first bit is directly latched by the SOTB10 register to the output latch at the falling (or rising) edge of SCK10,
and output from the SO10 pin via an output selector. Then, the value of the SOTB10 register is transferred to the
SIO10 register at the next rising (or falling) edge of SCK10, and shifted one bit. At the same time, the first bit of
the receive data is stored in the SIO10 register via the SI10 pin.
The second and subsequent bits are latched by the SIO10 register to the output latch at the next falling (or rising)
edge of SCK10, and the data is output from the SO10 pin.
The first bit is directly latched by the SOTB10 register at the falling edge of the write signal of the SOTB10
register or the read signal of the SIO10 register, and output from the SO10 pin via an output selector. Then, the
value of the SOTB10 register is transferred to the SIO10 register at the next falling (or rising) edge of SCK10, and
shifted one bit. At the same time, the first bit of the receive data is stored in the SIO10 register via the SI10 pin.
The second and subsequent bits are latched by the SIO10 register to the output latch at the next rising (or falling)
edge of SCK10, and the data is output from the SO10 pin.
Writing to SOTB10 or
Writing to SOTB10 or
reading from SIO10
reading from SIO10
Output latch
Output latch
SOTB10
SOTB10
(1) When CKP10 = 0, DAP10 = 0 (or CKP10 = 1, DAP10 = 0)
(2) When CKP10 = 0, DAP10 = 1 (or CKP10 = 1, DAP10 = 1)
SCK10
SCK10
SIO10
SIO10
SO10
SO10
Figure 15-7. Output Operation of First Bit
CHAPTER 15 SERIAL INTERFACE CSI10
User’s Manual U16962EJ3V0UD
First bit
First bit
2nd bit
2nd bit
3rd bit
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