UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 477

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(1) Shift register (SIO)
(2) SO latch
(3) Serial clock selector
(4) Serial clock counter
(5) Interrupt signal generator
(6) Serial clock control circuit
(7) Busy/acknowledge output circuit, bus release/command/acknowledge detection circuit
(8) Direction control circuit
The SIO converts 8-bit serial data to 8-bit parallel data, and vice versa. SIO is used for both transmission and reception.
Actual transmit/receive operations are controlled by writing to/reading from SIO.
SIO can be read or written to with an 8-bit manipulation instruction. The contents of SIO are undefined after RESET
input.
The SO latch holds the SO0/SB0 pin output level. This latch can also be directly controlled by software.
Selects the serial clock to be used.
Counts the serial clocks output or input in a transmit/receive operation, and checks that 8-bit data transmission/reception
has been performed.
Controls whether or not a interrupt request is generated when 8 serial clocks have been counted by the serial clock
counter. An interrupt request is generated every 8 clocks in 3-wire serial I/O mode, and when the condition is met in
SBI mode.
Controls the supply of the serial clock to the shift register (SIO), and also controls the clock output to the SCK0 pin
when the internal clock is used.
Performs output and detection of various control signals in serial bus interface (SBI) mode. Does not operate in 3-
wire serial I/O mode.
Controls the transmit/receive data shift direction.
CHAPTER 17 CLOCKED SERIAL INTERFACE
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