M95640-R datasheet(12/44 Pages) STMICROELECTRONICS

12 / 44 page

Operating features

M95320, M95640, M95320-x, M95640-x

12/44

4.1.4

Power-down

At Power-down (continuous decrease of VCC), as soon as VCC drops from the normal

operating voltage to below the Power On Reset threshold voltage, the device stops

responding to any instruction sent to it.

During Power-down, the device must be deselected and in Standby Power mode (that is

there should be no internal Write cycle in progress). Chip Select (S) should be allowed to

follow the voltage applied on VCC.

4.2

Active Power and Standby Power modes

When Chip Select (S) is Low, the device is selected, and in the Active Power mode. The

device consumes ICC, as specified in Table 13 to Table 17.

When Chip Select (S) is High, the device is deselected. If an Erase/Write cycle is not

currently in progress, the device then goes in to the Standby Power mode, and the device

consumption drops to ICC1.

4.2.1

Hold condition

The Hold (HOLD) signal is used to pause any serial communications with the device without

resetting the clocking sequence.

During the Hold condition, the Serial Data Output (Q) is high impedance, and Serial Data

Input (D) and Serial Clock (C) are Don’t Care.

To enter the Hold condition, the device must be selected, with Chip Select (S) Low.

Normally, the device is kept selected, for the whole duration of the Hold condition.

Deselecting the device while it is in the Hold condition, has the effect of resetting the state of

the device, and this mechanism can be used if it is required to reset any processes that had

been in progress.

The Hold condition starts when the Hold (HOLD) signal is driven Low at the same time as

Serial Clock (C) already being Low (as shown in Figure 5).

The Hold condition ends when the Hold (HOLD) signal is driven High at the same time as

Serial Clock (C) already being Low.

Figure 5 also shows what happens if the rising and falling edges are not timed to coincide

with Serial Clock (C) being Low.

Figure 5.

Hold condition activation

AI02029D

HOLD

Hold

Condition

Hold

Condition

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