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PXA300 Processor and PXA310 Processor
Vol. I: System and Timer Configuration Developers Manual
Doc. No. MV-TBD-00 Rev. A
CONFIDENTIAL
Copyright © 2006 Marvell
Page 116
Document Classification: Proprietary Information
December 13, 2006, Preliminary
Not approved by Document Control. For review only.
4.9
Edge-Detect Operation
Each multi-function pin can detect a rising or falling edge on the input (when enabled, this monitors the pin at all
times so an output transition would trigger it). The detection is controlled via the EDGE_CLEAR (which enables
and disables the function), and the edge_rise (if enabled, causes an event on rising edge), and the edge_fall (if
enabled causes an event on falling edge) register bits.
This purely combinational function detects an event based on the edge and not on a clock sampling a pulse
(although a small minimum pulse width is required). For example, for rising edge detect, an event is detected
when the signal is 0 initially, and then later it is 1.
Both edge detectors can be enabled, thus producing an event whenever the signal changed state (even briefly).
This edge-detect function provides a wake-up event in all power states to the device and is NOT connected to the
edge-detection function of the GPIO.
4.10
Low-Power Mode Operation
Low-power modes are defined as the state where the internal logical function is not operational but the pin is still
required to have a valid value (typically the default case). This is the case during D1 through D3 modes of
operation (in D4 mode the actual pins are powered off and no function is required). The multi-function pins in
this case are controlled by a combination of bits programmed into the MFPR xx registers for each pin. See
for more information.
In most cases, it is expected that the D1-D3 low-power mode behavior of a pin is as a logical output (driving
either 1 or 0), a pull high or low, or as a logical input. This behavior may be controlled via the SLEEP_DATA bit
(determining whether the output should be 1 or 0) and the SLEEP_OE bit (determining whether the pin should be
an output or an input). The pullup and pulldown functions are enabled only via the state of the PULLUP_EN and
PULLDOWN_EN bits (the PULL_SEL signal is overridden to 1 automatically when in the low power modes).
Thus, any possible state can be programmed in advance for D1-D3 low-power mode and then activated upon
entering the low-power mode.
NOTE: Output of three-state is identical to a simple input case. In this case, the output driver does not impact the input state.
However, the board must always drive this pin while in this mode to avoid any floating- node issues. This requirement is
the same as previous generations of processors with the change that this must be done in ALL states (except for
S3/D4/C4) of the device as there is no provision for disabling the input path.
Table 4-7. Low-Power Mode States
Output Value
SLEEP_OE_N
SLEEP_DATA
PULLUP_EN
PULLDOWN_EN
0
0
0
0
0
1
0
1
0
0
Pull high
1
X
1
0
Pull low
1
X
0
1
Three-state
1
X
0
0