8

COMMERCIAL AND INDUSTRIAL

TEMPERATURERANGES

IDT72V2101/72V2111 3.3V HIGH DENSITY CMOS

Number of

Words in

FIFO

0

0

(n+1) to 131,072

131,073 to (262,144-(m+1))

262,144

TABLE II

 STATUS FLAGS FOR FWFT MODE

IDT72V2101

IDT72V2111

FF

PAF HF

PAE EF

HH

HL

L

HH

HL

H

HH

H

H

H

HH

L

H

H

HL

L

H

H

LL

LH

H

TABLE I

 STATUS FLAGS FOR IDT STANDARD MODE

4669 drw 05

0

0

(n+2) to 262,145

262,146 to (524,289-(m+1))

(524,289-m)

(2)

to 524,288

524,289

IR

PAF HF PAE OR

LH

H

L

H

LH

H

L

L

L

H

HHL

LH

L

H

L

LLL

H

L

HL

L

H

L

IDT72V2101

IDT72V2111

Number of

Words in

FIFO

(n+1) to 262,144

262,145 to (524,288-(m+1))

524,288

(n+2) to 131,073

131,074 to (262,145-(m+1))

(262,145-m)

(2)

to 262,144

262,145

NOTES:

1. n = Empty Offset, Default Values: n = 127 when parallel offset loading is selected or n = 1,023 when serial offset loading is selected.

2. m = Full Offset, Default Values: m = 127 when parallel offset loading is selected or m = 1,023 when serial offset loading is selected.

NOTES:

1. n = Empty Offset, Default Values: n = 127 when parallel offset loading is selected or n = 1,023 when serial offset loading is selected.

2. m = Full Offset, Default Values: m = 127 when parallel offset loading is selected or m = 1,023 when serial offset loading is selected.

PROGRAMMING FLAG OFFSETS

FullandEmptyFlagoffsetvaluesareuserprogrammable.TheIDT72V2101/

72V2111hasinternalregistersfortheseoffsets.Defaultsettingsarestatedinthe

footnotesofTable1andTable2.OffsetvaluescanbeprogrammedintotheFIFO

inoneoftwoways;serialorparallelloadingmethod.Theselectionoftheloading

method is done using the

LD(Load)pin.DuringMasterReset,thestateofthe

LD input determines whether serial or parallel flag offset programming is

enabled. A HIGH on

LD during Master Reset selects serial loading of offset

valuesandinaddition,setsadefault

PAEoffsetvalueof3FFH(athreshold1,023

words from the empty boundary), and a default

PAF offset value of 3FFH (a

threshold 1,023 words from the full boundary). A LOW on

LD during Master

Resetselectsparallelloadingofoffsetvalues,andinaddition,setsadefault

PAE

offset value of 07FH (a threshold 127 words from the empty boundary), and

a default

PAF offset value of 07FH (a threshold 127 words from the full

boundary). See Figure 3, Offset Register Location and Default Values.

In addition to loading offset values into the FIFO, it also possible to read the

current offset values. It is only possible to read offset values via parallel read.

Figure 4, Programmable Flag Offset Programming Sequence, summa-

rizes the control pins and sequence for both serial and parallel programming

modes. For a more detailed description, see discussion that follows.

The offset registers may be programmed (and reprogrammed) any time

after Master Reset, regardless of whether serial or parallel programming

has been selected.