Chapter 16 Dual Output Voltage Regulator (VREG3V3V2) Block Description
Freescale Semiconductor
MC9S12C-Family / MC9S12GC-Family
469
Rev 01.24
16.5
Resets
This subsection describes how VREG3V3V2 controls the reset of the MCU.The reset values of registers
and signals are provided in
Section 16.3, “Memory Map and Register Definition”
. Possible reset sources
are listed in
16.5.1
Power-On Reset
During chip power-up the digital core may not work if its supply voltage V
DD
is below the POR
deassertion level (V
PORD
). Therefore, signal POR which forces the other blocks of the device into reset is
kept high until V
DD
exceeds V
PORD
. Then POR becomes low and the reset generator of the device
continues the start-up sequence. The power-on reset is active in all operation modes of VREG3V3V2.
16.5.2
Low-Voltage Reset
For details on low-voltage reset see
Section 16.4.6, “LVR — Low-Voltage Reset”
.
16.6
Interrupts
This subsection describes all interrupts originated by VREG3V3V2.
The interrupt vectors requested by VREG3V3V2 are listed in
. Vector addresses and interrupt
priorities are defined at MCU level.
16.6.1
LVI — Low-Voltage Interrupt
In FPM VREG3V3V2 monitors the input voltage V
DDA
. Whenever V
DDA
drops below level V
LVIA
the
status bit LVDS is set to 1. Vice versa, LVDS is reset to 0 when V
DDA
rises above level V
LVID
. An
interrupt, indicated by flag LVIF = 1, is triggered by any change of the status bit LVDS if interrupt enable
bit LVIE = 1.
NOTE
On entering the Reduced Power Mode, the LVIF is not cleared by the
VREG3V3V2.
Table 16-4. VREG3V3V2 — Reset Sources
Reset Source
Local Enable
Power-on reset
Always active
Low-voltage reset
Available only in Full Performance Mode
Table 16-5. VREG3V3V2 — Interrupt Vectors
Interrupt Source
Local Enable
Low Voltage Interrupt (LVI)
LVIE = 1; Available only in Full Performance Mode
Summary of Contents for MC9S12C Family
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