dspic33fj128gp706at-i-pt Microchip Technology Inc., dspic33fj128gp706at-i-pt Datasheet - Page 26

• Manufacturer Part Number: dspic33fj128gp706at-i-pt
• Description: High-performance, 16-bit Digital Signal Controllers
• Manufacturer: Microchip Technology Inc.

dsPIC33FJXXXGPX06A/X08A/X10A
2.7
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 < F
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
If MPLAB ICD 2, ICD 3 or REAL ICE 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
ADPCFG and ADPCFG2 registers.
The bits in the registers that correspond to the A/D pins
that are initialized by MPLAB ICD 2, ICD 3 or REAL
ICE, 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
ADPCFG and ADPCFG2 registers during initialization
of the ADC module.
When MPLAB ICD 2, ICD 3 or REAL ICE is used as a
programmer, the user application firmware must
correctly configure the ADPCFG and ADPCFG2
registers. Automatic initialization of these registers 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/O pins should be configured as outputs and
driven to a logic-low state.
Alternatively, connect a 1k to 10k resistor to V
unused pins and drive the output to logic low.
DS70593A-page 24
Oscillator Value Conditions on
Device Start-up
Configuration of Analog and
Digital Pins During ICSP
Operations
Unused I/Os
IN
< 8 MHz to comply with device PLL
SS
Preliminary
on
© 2009 Microchip Technology Inc.