Table of Contents
Advertisement
(1) SBI functions
With the conventional serial I/O method, when a serial bus is configured by connecting two or more
devices, many ports and wiring are necessary to distinguish chip select signals and command/data and
to judge the busy state because only a data transfer function is available. Controlling these operations
by software places a heavy load on the software.
In SBI, a serial bus can be configured with two signal lines: a serial clock SCK0 and serial data bus SB0
(SB1). Thus, SBI is effective to decrease the number of microcontroller ports and wiring and routing on
the board.
The SBI functions are described below.
(a) Address/command/data identification function
Serial data is distinguished into addresses, commands, and data.
(b) Chip select function by address transmission
The master executes slave chip selection by address transmission.
(c) Wakeup function
The slave can easily judge address reception (chip select judgment) using the wakeup function (which
can be set/reset by software).
When the wakeup function is set, the interrupt request signal (CSIIF0) is generated upon reception
of a match address. Thus, when communication is executed with two or more devices, the CPUs
of other than the selected slave device can operate irrespective of serial communication.
(d) Acknowledge signal (ACK) control function
The acknowledge signal to check serial data reception is controlled.
(e) Busy signal (BUSY) control function
The busy signal to report the slave busy state is controlled.
CHAPTER 13 SERIAL INTERFACE CHANNEL 0
User's Manual U11302EJ4V0UM
225
Advertisement
Table of Contents
