PXR40RM Datasheet, PDF (154/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

Power Management Controller (PMC)
Type
POR
POR
LVD
LVD
LVD
Table 5-7. POR and LVDs that Gate MCU Reset
Supply
VDDREG
VDD
VDD LVD
VDDSYN LVD
Reset LVD
Description
5V supply of the PMC block and bandgap (VDDREG)
1.2V core supply VDD
Core-voltage-supply VDD low-voltage
VDDSYN low voltage
Reset-pin-supply low-voltage
5.5.11 ADC Test Mux
During PMC functional mode it is possible to perform direct measurements through the ADC. PMC
internal voltages are routed to the ADC. Each signal can be measured with ADC running at full speed.
Table 5-8. ADC test mux channel for internal PMC signals
eQADC_A channel number
Signal propagated to ADC
ADC0 CH145
ADC0 CH146
ADC0 CH147
ADC0 CH180
ADC0 CH181
ADC0 CH182
ADC0 CH183
Band gap 0.62V
Analog supply 1.2V
VDD12OUT
LVD 1.2V
VDD33OUT
LVD 3.3V
LVD 5.0V
ADC1 CH196
LVD VDDA
Typical value (approximated)
0.62V (trimmed)
1.22V
Equal to VDD12OUT / 2.045
Equal to VLVD12 / 1.774
Equal to VDD33OUT / 5.460
Equal to VLVD33 / 4.758
Equal to VLVDREG / 4.758 in LDO mode;
(VLVDREG / 7.032 in SMPS mode)
Equal to VDDA LVD / 3.8934
Regulator feedback and LVD threshold signals propagated to ADC are a scaled down version of the
correspondent supply, by means of a resistive divider with programmable steps. The scaled signal read by
the ADC Vscaled will be approximately equal to the supply voltage Vsupply divided by the target voltage
(LVD or regulator output) Vtarget and multiplied by the band gap reference Vbg:
Vscaled=Vsupply*Vbg/Vtarget.
Eqn. 5-1
By measuring with ADC scaled supply voltage, supply voltage and bandgap voltage, it is possible to
calculate the approximate target LVD or regulator value. Vtarget is equal to: Vtarget=Vsupply*Vbg/Vadc.
During LVD measurement, the continuous time monitoring is temporarily disabled as the multiplexer
toggling could induce a false detection.
5-22
PXR40 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor