UPD70208HGF-16-3B9 NEC, UPD70208HGF-16-3B9 Datasheet - Page 29

• Manufacturer Part Number: UPD70208HGF-16-3B9
• Description: V40HLTM/ V50HLTM 16/8/ 16-BIT MICROPROCESSOR
• Manufacturer: NEC

8. REFU (REFRESH CONTROL UNIT)
interval can be set programmably.
8.1
8.2
is completely idle. However, if there are 7 or more pending refresh requests, it is given the highest priority, and it requests
the bus master holding the bus to relinquish it. (See 6. BAU.)
or by 2 (for the V50HL), and the next refresh address is generated.
The REFU generates refresh cycles required for refreshing of external DRAM. Refresh enabling/disabling and the refresh
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The REFU has two priorities. Normally, it has the lowest priority, and a refresh cycle cannot be started unless the bus
The refresh address is output on A0 to A15. Every refresh cycle the refresh address is incremented by 1 (for the V40HL)
In a refresh cycle, a low-level signal is output on the low address pins (A16 to A19).
This refresh address is not affected by a reset. When the device is powered on, the refresh address is undefined.
FEATURES
Lowest-priority refreshing/highest-priority refreshing
7-refresh queue
16-bit refresh address
REFRESH OPERATIONS
REFRQ extended timing supported (REFRQ active from T1 state)
Data Sheet U13225EJ4V0DS00
PD70208H, 70216H
29