MPC821 datasheet(153/242 Pages) NXP

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Support Information

MPC8XXFADS Design Specification—Rev 0.1

PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE

"******************************************************************************

equations

DramAdd.oe = 3;

when (!IS_HALF_WORD # IS_HALF_WORD & (SIMM36400 # SIMM36800)) then

DramAdd9 = A20;

else

DramAdd9 = A30;

when ( (SIMM36400 # SIMM36800) & !IS_HALF_WORD) then

DramAdd10 = A19;

else when ( (SIMM36400 # SIMM36800) & IS_HALF_WORD) then

DramAdd10 = A30;

else

DramAdd10 = 0;

"******************************************************************************

"* RAS generation.

"* Since the dram simm requires RAS signals to be split due to high capacitive

"* load and to allow 16 bit operation. When working with 16 bit port size,

"* the double drive RAS signals are disabled.

"******************************************************************************

equations

RAS.oe = ^hf;

!Ras1~ = !DramBank1Cs~ & DramBank2Cs~ & DRAM_ENABLED;

!Ras2~ = !DramBank2Cs~ & DramBank1Cs~ & DRAM_ENABLED & (SIMM36200 # SIMM36800);

!Ras1DD~ = !DramBank1Cs~ & DramBank2Cs~ & DRAM_ENABLED;

!Ras2DD~ = !DramBank2Cs~ & DramBank1Cs~ & DRAM_ENABLED & (SIMM36200 # SIMM36800);

"******************************************************************************

"* Flash Chip Select

"******************************************************************************

equations

FlashCsOut.oe = ^hf;

!FlashCs1~ = FLASH_ENABLED & !FlashCs~ & FLASH_BANK1;

!FlashCs2~ = FLASH_ENABLED & !FlashCs~ & FLASH_BANK2 ;

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

MPC821 데이터시트(PDF) 153 Page - NXP Semiconductors