UPD78F0078GK-9ET-A Renesas Electronics America, UPD78F0078GK-9ET-A Datasheet - Page 331

• Manufacturer Part Number: UPD78F0078GK-9ET-A
• Manufacturer: Renesas Electronics America

Specifications of UPD78F0078GK-9ET-A

• Lead Free Status / Rohs Status: Supplier Unconfirmed

(3) Timing of output to SO1 pin (first bit)
When communication is started, the value of transmit buffer register 1 (SOTB1) is output from the SO1 pin. The
following describes the output operation of the first bit at this time.
The first bit is directly latched to the output latch from the SOTB1 register at the falling (or rising) edge of SCK1,
passed through the output selector and output from the SO1 pin. The value of the SOTB1 register is transferred
to the SIO1 register at the next rising (or falling) edge of SCK1 and the data shifts by one bit. Simultaneously,
the first bit of the received data is passed through the SI1 pin and stored in the SIO1 register.
The second and subsequent bits are latched to the output latch at the next falling (or rising) edge of SCK1 and
the respective data is output from the SO1 pin.
The first bit is output from the SO1 pin directly from the SOTB1 register through the output selector at the falling
edge of the write signal of SOTB1 or the read signal of the SIO1 register. The value of the SOTB1 register is
transferred to the SIO1 register at the next falling (or rising) edge of SCK1 and shifts by one bit. Simultaneously,
the first bit of the received data is stored in the SIO1 register through the SI1 pin.
The second and subsequent bits are latched to the output latch from SIO1 at the next rising (or falling) edge of
SCK1 and the data is output from the SO1 pin.
SCK1
Writing to SOTB1 or
reading from SIO1
SOTB1
SIO1
Output latch
SO1
SCK1
Writing to SOTB1 or
reading from SIO1
SOTB1
SIO1
Output latch
SO1
(1) CKP1 = 0, DAP1 = 0 (or CKP1 = 1, DAP1 = 0)
(2) CKP1 = 0, DAP1 = 1 (or CKP1 = 1, DAP1 = 1)
Figure 17-8. Output Operation of First Bit
CHAPTER 17 SERIAL INTERFACE CSI1
User’s Manual U14260EJ4V0UD
First bit
First bit
2nd bit
2nd bit
3rd bit
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