Flash Power Supply, Power Saving And Reset; Power Supply; Sleep Mode; Shut-Down Mode - Infineon Technologies TC1796 User Manual

TC1796
System Units (Vol. 1 of 2)
Program Memory Unit
7.2.10

Flash Power Supply, Power Saving and Reset

This section describes some power supply, power saving mode, and reset related issues
of the Flash modules.

7.2.10.1 Power Supply

V
The TC1796 Flash module has a separate 3.3 V power supply line . It is used to
DDFL3
generate on-chip regulated voltages for the program and erase operations, as well as for
read operations.
If a power-fail occurs during a Flash erase or programming operation, a proper control
of the PORST input is required to avoid a possibly destructive operation (see Data Sheet
for details of power-fail control).

7.2.10.2 Sleep Mode

The TC1796 Flash module provides a sleep mode which makes it possible to reduce the
power consumption of the Flash module. Flash sleep mode is only entered if the Flash
module is in idle state with all pending or active operations processed and terminated.
Only in this case, the Flash module executes a ramp-down into Flash sleep mode. In
Flash sleep mode, all sense amplifiers are switched off, the internal voltages are ramped
down, and the Flash array oscillator is switched off. Next, status flag FSR.SLM is set
indicating an active Flash sleep mode.
Flash sleep mode can be initiated by software (separately from the other modules in the
TC1796) by setting bit FCON.SLEEP.
Flash sleep mode can also be initiated by hardware when the sleep mode is initiated by
the power management system of the TC1796 (see Section 5.1 on Page 5-2). A
TC1796 device sleep mode request affects the Flash module only if the external sleep
request disable bit FSR.ESLDIS is not set.
Wake-up from Flash sleep mode is initiated by clearing bit FCON.SLEEP or when the
device sleep mode signal from the power management system is released. In both
cases, the wake-up from sleep mode is controlled in the Flash module by starting the
Flash array oscillator again, ramping-up the internal voltages, and returning to read
mode. When again in read mode, also status flag FSR.SLM becomes cleared.
During ramp-down, active sleep mode, and wake-up from Flash sleep mode to active
mode, the Flash reports to be busy also by setting the bits FSR.PBUSY, FSR.D0BUSY,
and FSR.D1BUSY.

7.2.10.3 Shut-Down Mode

The Flash module can also be put into a shut-down mode in which it is switched off
completely and cannot be used at all. This shut-down mode is not available for a user
User's Manual 7-38 V2.0, 2007-07
PMU, V2.0