參數(shù)資料
型號： UPD70433R-12
廠商： NEC Corp.
元件分類： 16位微控制器
英文描述： V55PITM 16-BIT MICROPROCESSOR
中文描述： V55PITM 16位微處理器
文件頁數(shù)： 41/166頁
文件大?。?/td> 772K
代理商： UPD70433R-12
41
μ
PD70433
4.2
REFRESH FUNCTION
The following functions are provided to refresh DRAM and pseudo-SRAM.
Function to insert periodically a refresh cycle in a series of bus cycles
Refresh address output function to refresh DRAM and pseudo-SRAM
Function to generate a refresh cycle in hold mode and HALT mode.
Function to insert a wait state in a refresh cycle
4.2.1
Refresh Mode Register (RFM)
The RFM register is an 8-bit register to control refresh operation.
A refresh cycle can be selected from the time base counter output tap.
While a refresh request is held by another bus cycle if the next refresh request is generated, only the latter is valid.
The RFM register value after a reset is 77H.
4.2.2
Wait Control in Refresh Cycle
A wait state can be inserted in a refresh cycle. The specified number of wait states is inserted for memory block 4 by
the programmable wait control register (PWC0) or READY pin.
4.2.3
Refresh Address
Bus pins AD0 to AD15 and A16 to A19 are activated in a refresh cycle.
For each refresh cycle, the count is performed in one-address increments from x00000 to x1FFFFF in the case of the
external 8-bit bus width, and in two-address increments from x00001H to xFFFFF in the case of the external 16-bit bus width
(the minimum address is returned to after the maximum address).
After initialization by a reset, count-up is started from x00000H in the case of the external 8-bit bus width and x00001H
in the case of the external 16-bit bus width.
In the case of the external 16-bit bus width, the refresh address minimum address bit (A0) is fixed at “1” and the DEX
pin output is also fixed at “1”.
A20 to A23 are undefined in a refresh cycle.
相關PDF資料
PDF描述
UPD70433R-16 V55PITM 16-BIT MICROPROCESSOR
UPD70433GD-12-5BB V55PITM 16-BIT MICROPROCESSOR
UPD70433GD-16-5BB V55PITM 16-BIT MICROPROCESSOR
UPD70433GJ-12-3EB V55PITM 16-BIT MICROPROCESSOR
UPD70433GJ-16-3EB V55PITM 16-BIT MICROPROCESSOR
相關代理商/技術參數(shù)
參數(shù)描述
UPD70433R-16 制造商:NEC 制造商全稱:NEC 功能描述:V55PITM 16-BIT MICROPROCESSOR
UPD705100 制造商:NEC 制造商全稱:NEC 功能描述:V830TM 32-BIT MICROCONTROLLER
UPD705100GJ-100-8 制造商:NEC 制造商全稱:NEC 功能描述:V830TM 32-BIT MICROCONTROLLER
UPD705100GJ-100-8EU 制造商:NEC 制造商全稱:NEC 功能描述:V830TM 32-BIT MICROCONTROLLER
UPD705101 制造商:NEC 制造商全稱:NEC 功能描述:32-BIT MICROPROCESSOR
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