TC1784
Program Memory Unit (PMU)
User´s Manual
5-89
V1.1, 2011-05
PMU, V1.47
5.6.7
Power Supply and Reset
The following chapters describe the required power supplies, the power consumption
and its possible reduction, the control of Flash Sleep Mode and the basic control of
Reset.
5.6.7.1
Power Supply
The flash module uses the standard
V
DDP
I/O power supply to generate the voltages for
both read and write functions. A VPP pin is not used for write operations. Internally
generated and regulated voltages are provided for the program and erase operations as
well as for read operations. The standard
V
DD
is used for all digital control functions.
5.6.7.2
Flash Power Consumption
For dynamic reduction of power consumption, the PMU controls the activity of the word
line drivers of the Flash array, if enabled in the FCON register. If this dynamic power
reduction is enabled, the read performance is slightly reduced because the control of
prefetching is limited in this case. In DFlash, dynamic power reduction is provided per
default, because DFlash prefetching is not supported.
5.6.7.3
Flash Sleep Mode
As power reduction feature, the Flash module provides a Flash sleep mode which can
be selected by the user individually for the Flash, if the FCON-bit 15 (SLEEP) is set.
Additionally, the sleep mode can be requested by a global SLEEP signal from a Power
Management System. This ‘external’ sleep request signal is only accepted by Flash state
machines, when it is not disabled with the FCON-bit ESLDIS.
The requested sleep mode is only taken if the Flash is in idle state and when all pending
or active requests are processed and terminated. Only then, the Flash array performs
the ramp down into the sleep mode: the sense amplifiers are switched off, the voltages
are ramped down and the array-oscillator is switched off.
As long as the Flash is in sleep mode, this state is indicated by the SLM bit in the Flash
Status Register FSR.
Wake-up from sleep is controlled with clearing of bit FCON.15, if selected via this bit, or
wake-up is initialized by trailing edge of the broadcasted (’external’) sleep signal from
SCU. After wake-up, the Flash oscillator is switched on, the voltages are ramped up and
the Flash takes the read mode. Note: A wake-up is only accepted by the Flash in its sleep
mode; it is not accepted while it is ramped down.
Note: During ramp-down, sleep and wake-up, the Flash is reported to be busy. Thus,
read and write accesses to the Flash in sleep mode are acknowledged with ‘retry’
and should therefore be avoided; those accesses make sense only during wake-
up, when waiting for the Flash read mode.
Summary of Contents for TC1784
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Page 950: ...TC1784 Direct Memory Access Controller DMA User s Manual 11 132 V1 1 2011 05 DMA V3 03 ...
Page 1949: ...TC1784 General Purpose Timer Array GPTA v5 User s Manual 21 297 V1 1 2011 05 GPTA v5 V1 14 ...
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