NEC PD75402A - Manual (Page 82)

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CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS
(3) SBI mode (serial bus interface mode)
In the SBI mode, communication is performed with multiple devices by means of two lines: The serial clock (SCK)
and the serial data bus (SB0).
This mode conforms to the NEC serial bus format.
In the SBI mode, the sender can output to the serial data bus an address to select the target device for serial
communication, a command which gives a directive to the target device, and actual data. The receiver can determine
by hardware whether the received data is an address, command or actual data.
Fig. 5-23 Example of SBI System Configuration
Note When the
µ
PD75402A is used as a slave CPU, its address is limited to the range C0H to C7H.
5.5.2 Serial Interface Configuration
The serial interface block diagram is shown in Fig. 5-24.
Master CPU
SCK SCK
Serial Clock
Address
Command
Data
Slave IC
SCK
Address N #N
SB0
SB0 SB0
V
DD
Address 1 #1
Slave CPU