UPD75236 Datasheet, PDF (90/190 Pages) NEC – 4-BIT SINGLE-CHIP MICROCOMPUTER

µPD75236
(d) Slave address register (SVA)
The slave address register (SVA) has the following two functions.
Only write is enabled for the SVA by an 8-bit manipulation instruction.
RESET input makes the SVA value undefined. RESET input in the standby mode holds the SVA
value.
• Slave address detection
[SBI mode]
Use this mode to connect the µPD75236 as a slave device to the serial bus. The SVA is an 8-bit
register for the slave to set the slave address value (own specification number). The master outputs
a slave address for particular slave selection to the connected slave. These two date (salve address
and SVA values output from the master) are compared by an address comparator. When they match,
the slave has been selected.
In this case, bit 6 (COI) of the serial operating mode register 0 (CSIM0) is set to “1”.
Note
1. The slave selection or non-selection status is checked by detecting the matching of the slave
address received after bus release (RELD = 1).
Use the address match interrupt (IRQCSI0) to be normally generated with WUP = 1 to detect the
matching. Thus, detect selection or non-selection by slave address when WUP = 1.
2. If selection or non-selection is to be detected without using an interrupt when WUP = 0, do so by
transmitting/receiving the command preset by a program without using the method of detecting
address matching.
• Error detection
[2-wire serial I/O and SBI modes]
When an address, a command and data are to be transmitted using the µPD75236 as the master
device or data is to be transmitted using the µPD75236 as the slave device, the SVA detects errors.
(4) Various types of signals
Table 4-6 gives a list of various types of signals. Figs. 4-43 to 4-48 show the various types of signals
and flag operation.
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