Datasheet

Signal description M950x0-W M950x0-R M950x0-DF
10/45 DocID6512 Rev 12
2.8.3 Power-up conditions
When the power supply is turned on, V
CC
rises continuously from V
SS
to V
CC
. During this
time, the Chip Select (
S) line is not allowed to float but should follow the V
CC
voltage. It is
therefore recommended to connect the
S line to V
CC
via a suitable pull-up resistor (see
Figure 3: Bus master and memory devices on the SPI bus).
In addition, the Chip Select (S) input offers a built-in safety feature, as the S input is edge
sensitive as well as level sensitive: after power-up, the device does not become selected
until a falling edge has first been detected on Chip Select (
S). This ensures that Chip Select
(
S) must have been high, prior to going low to start the first operation.
The V
CC
voltage has to rise continuously from 0 V up to the minimum V
CC
operating voltage
defined in
Table 9: Operating conditions (M950x0-W), Table 10: Operating conditions
(M950x0-R) and Table 11: Operating conditions (M95040-DF, device grade 6) and the rise
time must not vary faster than 1 V/µs.
2.8.4 Power-down
During power-down (continuous decrease in the V
CC
supply voltage below the minimum
V
CC
operating voltage defined in Table 9: Operating conditions (M950x0-W), Table 10:
Operating conditions (M950x0-R) and Table 11: Operating conditions (M95040-DF, device
grade 6)), the device must be:
 Deselected (Chip Select S should be allowed to follow the voltage applied on V
CC
)
 In Standby Power mode (there should not be any internal write cycle in progress).