241
CHAPTER 13 SERIAL INTERFACE CHANNEL 0
(6) Address match detection method
In the SBI mode, a particular slave device is selected by slave address transmission by the master device.
Address coincidence is automatically detected by hardware. When the wake-up function specification bit
(WUP) = 1, CSIIF0 is set if the slave address transmitted from the master coincides with the address set to
the slave address register (SVA).
While bit 5 (SIC) of the interrupt timing specification register (SINT) is set (1), the wake-up function does not
operate even if WUP is set to 1 (instead, an interrupt request signal is generated on detection of bus release).
Clear SIC to 0 when the wake-up function is used.
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 request (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 request 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 13-27 to 13-30 show data communication timing charts.
Shift operation of the serial I/O shift register 0 (SIO0) 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 SIO0.