NEC PD78214 - Manual (Page 316)

287
Chapter 10 Clock Synchronous Serial Interface
10
10.6.8 Communication
In SBI communication, the master device outputs an address on the serial bus and, usually, one target slave device
is selected out of two or more devices according to the address.
Once the target device has been determined, commands and data are transferred between the master device and
slave device to implement serial communication.
Figs. 10-27 to 10-30 show the timing charts for data communication.
10.6.9 Releasing the Busy State
The conditions governing the release of the busy state depend on whether transmission or reception is permitted.
They can be applied to high-speed transfer using the SBI macro service. Table 10-3 lists the methods of releasing
the BUSY state.
Table 10-3 Conditions Governing Release of BUSY
Divice and condition
CTxE
0
0
1
1
CRxE
0
1
0
1
BSYE ←0, SIO read access
BSYE ←0, SIO write access Note
Conditions governing the release of BUSY
Note Write FFH into the SIO if the next operation is reception.
10.6.10 Setting Wake-Up
If WUP is set to 1 in the busy state, the wake-up state is set as soon as the device enters the ready state.
In the wake-up state, an interrupt (INTCSI) is issued only when an address is received. The acknowledge (ACK)
signal is not detected in this state.
10.6.11 Starting Transmission and Reception
Start transmission and reception in the same way as the busy state is released. Even if start of transmission and
reception is specified, transmission and reception are not started while the slave device is outputting the BUSY
signal. Transmission and reception are started when the busy state is released.