DS28EC20

Analog Devices, Inc.

21 of 28

Figure 9-2. ROM Functions Flowchart (continued)

From Figure 9,

1st Part

From Figure 9,

1st Part

To Figure 9, 1st Part

RC = 1 ?

N

Y

RC = 0 ; OD = 1

Controller TX Bit 0

Controller TX Bit 63

Controller TX Bit 1

RC = 1

Bit 0

Match?

Y

N

Bit 1

Match?

Y

N

Bit 63

Match?

Y

N

Y

N

69h

Overdrive Match

ROM?

RC = 0 ; OD = 1

Controller

TX Reset ?

Y

N

Controller

TX Reset ?

N

Y

Y

N

3Ch

Overdrive

Skip ROM?

Y

N

A5h

Resume

Command?

To Figure 9,

1st Part

OD = 0

OD = 0

OD = 0

1)

1)

1)

1) The OD flag remains at 1 if the device was already at overdrive

speed before the Overdrive Match ROM command was issued.

NOTE: For operation at overdrive speed, the DS28EC20 requires VPUP to be between 4V and 5.25V.