DSPIC33FJ16GS504T-E Datasheet, PDF (24/346 Pages) Microchip Technology – High-Performance, 16-bit Digital Signal Controllers

dsPIC33FJ06GS101/X02 and dsPIC33FJ16GSX02/X04
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, 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 register.
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 firm-
ware; 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 register during initialization of the ADC mod-
ule.
When MPLAB ICD 2, ICD 3, or REAL ICE is used as a
programmer, the user application firmware must
correctly configure the ADPCFG register. 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 func-
tionality.
2.9 Unused I/Os
Unused I/O pins should be configured as outputs and
driven to a logic-low state.
Alternatively, connect a 1k to 10k resistor to VSS on
unused pins and drive the output to logic low.
2.10 Typical Application Connection
Examples
Examples of typical application connections are shown
in Figure 2-4 through Figure 2-11.
DS70318D-page 22
Preliminary
© 2009 Microchip Technology Inc.