UPD17073 NEC, UPD17073 Datasheet - Page 122

• Manufacturer Part Number: UPD17073
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER WITH HARDWARE FOR DIGITAL TUNING SYSTEM
• Manufacturer: NEC

14.8 Notes on Setting and Reading Data
instruction to read data.
depending on the status of the shift clock pin.
122
Wait
status
Wait
release
status
Use the “PUT SIOSFR, DBF” instruction to set data to the presettable shift register. Use the “GET DBF, SIOSFR”
Set or read the data in the wait status. While the wait status is released, the data may not be correctly set or read
The following table describes the points to be noted in setting and reading data.
Status on execution
of PUT/GET
Table 14-2. Data Read and Write Operations of Presettable Shift Register and Notes
Read (GET)
Write (PUT)
Read (GET)
Write (PUT)
• Floating with external
• Value of output latch
Low level
High level
Low level
High level
Status of shift clock pin
clock
with internal clock.
Normally, used with
high level
Normal read
Normal write
Content of MSB is output as data at falling edge of shift clock
after wait status is released next (transmission operation).
Normal read
Cannot be read normally.
Contents of SIOSFR are lost.
Cannot be written normally.
Contents of SIOSFR are lost.
Normal write
Content of MSB is output as data when PUT instruction is
executed.
Clock counter is not reset.
Clock
Data
Clock
Data
PUT SIOSFR, DBF
Operation of presettable shift register
PUT SIOSFR, DBF
MSB
Wait released
PD17072,17073
MSB