NEC PD75402A User Manual page 93

(4) Slave address register (SVA)
SVA is an 8-bit register used by the slave to set the slave address value (its own specification number).
SVA is a write-only register which is manipulated by 8-bit manipulation instructions.
After RESET signal input, the value of SVA is indeterminate. However, when RESET is input in the standby mode,
the value of SVA is retained.
In the SBI mode, the slave address register (SVA) has the following two functions:
(a) Slave address detection
Used when the PD75402A is connected to the serial bus as a slave device.
The high-order 5 bits of the SVA register are fixed at 11000 by hardware. Therefore, the address assigned
to the PD75402A is limited to the range C0H to C7H.
The master outputs to its connected slaves a slave address to select a specific slave. If these two data items
(the slave address output from the master and the SVA value) are found to match when compared by the
address comparator, the relevant slave is determined to have been selected.
At this time, bit 6 (COI) of the serial operating mode register (CSIM) is set to "1".
When an address is received the bus release detection flag (RELD) is cleared (0) if a match is not detected.
IRQCSI is set only when a match is detected when WUP = 1. This interrupt request indicates that a
communication request has been issued from the master to the PD75402A.
(b) Error detection
The SVA performs error detection in the following cases:
• When the PD75402A transmits addresses, commands or data as the master device.
• When the PD75402A transmits data as a slave device.
See 5.5.6 (8) "Error detection" for details.
Note When data is written to SVA, ensure that a value between C0H and C7H is written.
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CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS