MPC5604B/C Microcontroller Reference Manual, Rev. 8
Freescale Semiconductor 593
Analog watchdogs allow continuous hardware monitoring.
25.3 Functional description
25.3.1 Analog channel conversion
Three conversion modes are available within the ADC:
• Normal conversion
• Injected conversion
• CTU triggered conversion
25.3.1.1 Normal conversion
This is the normal conversion that the user programs by configuring the normal conversion mask registers
(NCMR). Each channel can be individually enabled by setting ‘1’ in the corresponding field of NCMR
registers. Mask registers must be programmed before starting the conversion and cannot be changed until
the conversion of all the selected channels ends (NSTART bit in the Main Status Register (MSR) is reset).
25.3.1.2 Start of normal conversion
By programming the configuration bits in the Main Configuration Register (MCR), the normal conversion
can be started in two ways:
• By software (TRGEN reset)—If the external trigger enable bit is reset, the conversion chain starts
when the MCR[NSTART] bit is set.
• By trigger (TRGEN set)—An on-chip internal signal triggers an ADC conversion. The settings in
the MCR select how conversions are triggered based on these internal signals:
— If the EDGLEV (edge/level selection) bit in the MCR is cleared, then a rising/falling edge
(depending on the MCR[EDGE] bit) detected in the signal sets the MSR[NSTART] bit and
starts the programmed conversion. EDGE = 0 selects a falling edge. EDGE = 1 selects a rising
edge.
— If the EDGLEV bit in the MCR is set, the conversion is started if and only if the
MCR[NSTART] bit is set and the programmed level on the trigger signal is detected. The level
is selected using the MCR[EDGE] bit. EDGE = 0 means that the start of conversion is enabled
if the signal is low. If EDGE = 1, the start of conversion is enabled when the signal is high.
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