DSPIC33FJMC202ESS datasheet(16/330 Pages) MICROCHIP

16 / 330 page

dsPIC33FJ32MC202/204 and dsPIC33FJ16MC304

DS70283K-page 16

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

≤8 MHz for start-up with PLL enabled. This means

that if the external oscillator frequency is outside this

range, the application must start-up in 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 auto-

matically initializes all of the A/D input pins (ANx) as

“digital” pins, by setting all bits in the AD1PCFGL regis-

ter.

The bits in the registers that correspond to the A/D pins

that are initialized by 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 3 or MPLAB REAL ICE™ in-circuit

emulator is used as a programmer, the user application

firmware must correctly configure the AD1PCFGL

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.

Alternatively, connect a 1k to 10k resistor between VSS

and the unused pins.

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