Power Management Controller (PMC)
5-22
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
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.
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.
Table 5-7. POR and LVDs that Gate MCU Reset
Type
Supply
Description
POR
VDDREG
5V supply of the PMC block and bandgap (VDDREG)
POR
VDD
1.2V core supply VDD
LVD
VDD LVD
Core-voltage-supply VDD low-voltage
LVD
VDDSYN LVD
VDDSYN low voltage
LVD
Reset LVD
Reset-pin-supply low-voltage
Table 5-8. ADC test mux channel for internal PMC signals
eQADC_A channel number
Signal propagated to ADC
Typical value (approximated)
ADC0 CH145
Band gap 0.62V
0.62V (trimmed)
ADC0 CH146
Analog supply 1.2V
1.22V
ADC0 CH147
VDD12OUT
Equal to VDD12OUT / 2.045
ADC0 CH180
LVD 1.2V
Equal to VLVD12 / 1.774
ADC0 CH181
VDD33OUT
Equal to VDD33OUT / 5.460
ADC0 CH182
LVD 3.3V
Equal to VLVD33 / 4.758
ADC0 CH183
LVD 5.0V
Equal to VLVDREG / 4.758 in LDO mode;
(VLVDREG / 7.032 in SMPS mode)
ADC1 CH196
LVD VDDA
Equal to VDDA LVD / 3.8934
Summary of Contents for PXR4030
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