UPD703111A Datasheet, PDF (370/974 Pages) NEC – 32-Bit Single-Chip Microcontroller

CHAPTER 8 CLOCK GENERATION FUNCTION
(2/2)
To change the refresh interval, set a value at which refresh can be made in time even
while the interval is changed (see 8.3.1 (1) Notes on changing refresh interval). If the
refresh interval is correctly secured with the interrupt servicing time taken into
consideration, the processing in <1> above may be skipped. The RFSn and BCTm
registers are prohibited from being rewritten, but they can be rewritten when the
refreshing interval is re-set by changing the value of the CKC register.
A register setting cycle of SDRAM is generated as a result of rewriting the SCRn register
(processing in <6> above), but the value of SDRAM before the RFSn and SCRn registers
are re-set is retained.
370
User’s Manual U16031EJ4V1UD