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CHAPTER 15 SERIAL INTERFACE CHANNEL 0 (
m
PD78064 Subseries)
(6) Address match detection method
In the SBI mode, a particular slave device is selected by address communication from the master device and
communication is started.
Address match detection is executed by hardware. With the slave address register (SVA), CSIIF0 is set in
the wake-up state (WUP = 1) only when the address transmitted from the master device matches the value
set to SVA.
Cautions 1. Slave selection/non-selection is detected by matching of the slave address received after
bus release (RELD = 1).
For this match detection, match interrupt (INTCSI0) of the address to be generated with
WUP = 1 is normally used. Thus, execute selection/non-selection detection by slave
address when WUP = 1.
2. When detecting selection/non-selection without the use of interrupt with WUP = 0, do
so by means of transmission/reception of the command preset by program instead of
using the address match detection method.
(7) Error detection
In the SBI mode, the serial bus SB0 (SB1) status being transmitted is fetched into the destination device,
that is, the serial I/O shift register 0 (SIO0). Thus, transmit errors can be detected in the following way.
(a) Method of comparing SIO0 data before transmission to that after transmission
In this case, if two data differ from each other, a transmit error is judged to have occurred.
(b) Method of using the slave address register (SVA)
Transmit data is set to both SIO0 and SVA and is transmitted. After termination of transmission, COI
bit (match signal coming from the address comparator) of the serial operating mode register 0 (CSIM0)
is tested. If “1”, normal transmission is judged to have been carried out. If “0”, a transmit error is judged
to have occurred.
(8) Communication operation
In the SBI mode, the master device selects normally one slave device as communication target from among
two or more devices by outputting an “address” to the serial bus.
After the communication target device has been determined, commands and data are transmitted/received
and serial communication is realized between the master and slave devices.
Figures 15-27 to 15-30 show data communication timing charts.
Shift operation of the shift register is carried out at the falling edge of serial clock (SCK0). Transmit data is
latched into the SO0 latch and is output with MSB set as the first bit from the SB0/P25 or SB1/P26 pin. Receive
data input to the SB0 (or SB1) pin at the rising edge of SCK0 is latched into the shift register.