PC8477B datasheet(43/54 Pages) NSC

43 / 54 page

60 Device Description (Continued)

625 DMA Timing

Symbol

Parameter

Min

Max

Units

tQP

DRQ Period (Except Non-Burst DMA) (Note 8)

8 x tDRP

tQQ

DRQ Inactive Non-Burst Pulse Width

300

400

tKQ

DACK Active Edge to DRQ Inactive

tRQ

RD WR Active Edge to DRQ Inactive (Note 7)

tQR

DRQ to RD WR Active

tTT

TC Active Pulse Width

tTQ

TC Active Edge to DRQ Inactive (Note 9)

tKK

DACK Active Pulse Width

tKI

DACK Inactive Pulse Width

tKR

DACK Setup to RD WR Active

tRK

DACK Hold from RD WR Inactive

tQW

DRQ to End of RD WR (Note 8)

(8 x tDRP

(DRQ Service Time)

16xtICP)

tQT

DRQ to TC Active (Note 8)

(8 x tDRP

(DRQ Service Time)

16xtICP)

Note 7

The active edge of RD or WR is recognized only when DACK is active

Note 8

Values shown are with the FIFO disabled or with FIFO enabled and THRESH e 0 For nonzero values of THRESH add (THRESHx8xtDRP) to the values

shown

Note 9

During normal DMA operation TC should occur when DACK is active during the last byte of the last sector transferred

TLF11332 – 19

FIGURE 6-4 DMA Timing

PC8477B Datasheet(PDF) 43 Page - National Semiconductor (TI)

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