DSPIC33FJ12MC201_11 Datasheet, PDF (18/304 Pages) Microchip Technology – High-Performance, 16-bit Digital Signal Controllers

dsPIC33FJ12MC201/202
2.7 Oscillator Value Conditions on
Device Start-up
If the PLL of the target device is enabled and
configured for the device start-up oscillator, the
maximum oscillator source frequency must be limited
to 4 MHz < FIN < 8 MHz to comply with device PLL
start-up conditions. This means that if the external
oscillator frequency is outside this range, the
application must start-up in the FRC mode first. The
default PLL settings after a POR with an oscillator
frequency outside this range will violate the device
operating speed.
Once the device powers up, the application firmware
can initialize the PLL SFRs, CLKDIV, and PLLDBF to a
suitable value, and then perform a clock switch to the
Oscillator + PLL clock source. Note that clock switching
must be enabled in the device Configuration word.
2.8 Configuration of Analog and
Digital Pins During ICSP
Operations
If MPLAB ICD 2, MPLAB ICD 3, or MPLAB REAL ICE
in-circuit emulator is selected as a debugger, it
automatically initializes all of the A/D input pins (ANx)
as “digital” pins, by setting all bits in the AD1PCFGL
register.
The bits in the register that correspond to the A/D pins
that are initialized by MPLAB ICD 2, MPLAB ICD 3, or
MPLAB REAL ICE in-circuit emulator, must not be
cleared by the user application firmware; otherwise,
communication errors will result between the debugger
and the device.
If your application needs to use certain A/D pins as
analog input pins during the debug session, the user
application must clear the corresponding bits in the
AD1PCFGL register during initialization of the ADC
module.
When MPLAB ICD 2, MPLAB ICD 3, or MPLAB REAL
ICE in-circuit emulator is used as a programmer, the
user application firmware must correctly configure the
AD1PCFGL register. Automatic initialization of this
register is only done during debugger operation.
Failure to correctly configure the register(s) will result in
all A/D pins being recognized as analog input pins,
resulting in the port value being read as a logic ‘0’,
which may affect user application functionality.
2.9 Unused I/Os
Unused I/O pins should be configured as outputs and
driven to a logic-low state.
Alternately, connect a 1k to 10k resistor between VSS
and unused pins and drive the output to logic low.
DS70265E-page 18
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