Fujitsu FR60 Hardware Manual page 483

■ Slave Address Detection
In slave mode, BB=1 is set after a START condition is generated. The transmitted data from the master is
stored in the IDAR register.
[When a 7-bit slave address is enabled] (ISMK ENSB=1)
After 8-bit data is received, the IDAR and ISBA register values are compared.
At this time, the values are compared with the values of the bits masked with the ISMK register.
If the comparison result is a match, the AAS bit is set to "1" and an acknowledge is sent to the master.
The value of bit 0 of the received data (bit 0 of the IDAR register after reception) is then inverted and
stored in the TRX bit.
[When a 10-bit slave address is enabled] (ITMK ENTB=1)
If the header section of a 10-bit address (11110, TA1, TA0, write) is detected, an acknowledge is sent to
the master, and the value of bit 0 of received data is inverted and stored in the TRX bit. No interrupt
occurs at this time.
Then, the next data to be transferred and the low-order data of the ITBA register are compared. They are
compared with the values of the bits masked with the ISMK register at this time.
If the result is a match, the AAS bit is set to "1", an acknowledge is sent to the master, and an interrupt
occurs.
If the address has been specified as a slave and a repeated START condition is detected, the AAS bit is
set to "1" and an interrupt occurs after the header section of a 10-bit address (11110, TA1, TA0, read) is
received.
The interface has a 10-bit slave address register (ITBA) and a 7-bit slave address register (ISBA). If both
registers are enabled (ISMK ENSB = 1, ITMK ENTB = 1), an acknowledge can be sent for the 10-bit and
7-bit addresses.
The receive slave address length in slave mode (AAS = 1) is determined by the RAL bit of the ITMK
register. In master mode, disabling both registers (ISMK ENSB = 0, ITMK ENTB = 0) can prevent a
slave address from being generated for the I
All slave addresses can be masked by setting the ITMK and ISMK registers.
■ Slave Address Mask
The slave address mask registers (ITMK and ISMK) can mask each bit of the slave address registers. A
bit set to "1" in the mask register is address-compared while a bit set to "0" is ignored. In slave mode
(IBSR AAS = 1), a receive slave address can be read from the ITBA register (for a 10-bit address) or the
ISBA register (for a 7-bit address).
If the bit mask is cleared, the interface can be used as the bus monitor because it is always accessed as a
slave.
Note:
This feature does not become a real bus monitor because it returns an acknowledge when a slave
address is received even though no other slave device is available.
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C interface.
15.4 Operation Flowcharts