MA240017 Microchip Technology, MA240017 Datasheet - Page 100

• Manufacturer Part Number: MA240017
• Description: MODULE PLUG-IN PIC24F16KA102 PIM
• Manufacturer: Microchip Technology
• Series: PIC®r

Specifications of MA240017

• Accessory Type: Plug-In Module (PIM) - PIC24F16KA102
• Product: Microcontroller Modules
• Data Bus Width: 16 bit
• Core Processor: PIC24F16KA102
• Operating Supply Voltage: 3 V to 3.6 V
• Development Tools By Supplier: Integrated Development Environment, Assembler, ANSI C Compiler
• Processor Series: PIC24F
• Silicon Manufacturer: Microchip
• Core Architecture: PIC
• Core Sub-architecture: PIC24
• Silicon Core Number: PIC24F
• Silicon Family Name: PIC24FxxKAxx
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: Explorer 16 (DM240001 or DM240002)
• For Use With: DM240001 - BOARD DEMO PIC24/DSPIC33/PIC32
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PIC24F16KA102 FAMILY
The following code sequence for a clock switch is
recommended:
1.
2.
3.
4.
5.
6.
7.
8.
The core sequence for unlocking the OSCCON register
and initiating a clock switch is provided in Example 9-1.
EXAMPLE 9-1:
DS39927B-page 98
;Place the new oscillator selection in W0
;OSCCONH (high byte) Unlock Sequence
MOV
MOV
MOV
MOV.b
MOV.b
;Set new oscillator selection
MOV.b
;OSCCONL (low byte) unlock sequence
MOV
MOV
MOV
MOV.b
MOV.b
;Start oscillator switch operation
BSET
Disable interrupts during the OSCCON register
unlock and write sequence.
Execute the unlock sequence for the OSCCON
high
OSCCON<15:8> in two back-to-back instructions.
Write new oscillator source to the NOSCx bits in
the instruction immediately following the unlock
sequence.
Execute the unlock sequence for the OSCCON
low
OSCCON<7:0> in two back-to-back instructions.
Set the OSWEN bit in the instruction immediately
following the unlock sequence.
Continue to execute code that is not
clock-sensitive (optional).
Invoke an appropriate amount of software delay
(cycle counting) to allow the selected oscillator
and/or PLL to start and stabilize.
Check to see if OSWEN is ‘0’. If it is, the switch
was successful. If OSWEN is still set, then check
the LOCK bit to determine the cause of failure.
byte
byte
#OSCCONH, w1
#0x78, w2
#0x9A, w3
w2, [w1]
w3, [w1]
WREG, OSCCONH
#OSCCONL, w1
#0x46, w2
#0x57, w3
w2, [w1]
w3, [w1]
OSCCON,#0
by
by
writing
writing
BASIC CODE SEQUENCE
FOR CLOCK SWITCHING
46h
78h
and
and
9Ah
57h
to
to
Preliminary
9.5
In addition to the CLKO output (F
certain oscillator modes, the device clock in the
PIC24F16KA102 family devices can also be configured
to provide a reference clock output signal to a port pin.
This feature is available in all oscillator configurations
and allows the user to select a greater range of clock
submultiples to
application.
This reference clock output is controlled by the
REFOCON register (Register 9-4). Setting the ROEN
bit (REFOCON<15>) makes the clock signal available
on the REFO pin. The RODIV bits (REFOCON<11:8>)
enable the selection of 16 different clock divider
options.
The ROSSLP and ROSEL bits (REFOCON<13:12>)
control the availability of the reference output during
Sleep mode. The ROSEL bit determines if the oscillator
on OSC1 and OSC2, or the current system clock
source, is used for the reference clock output. The
ROSSLP bit determines if the reference source is
available on REFO when the device is in Sleep mode.
To use the reference clock output in Sleep mode, both
the ROSSLP and ROSEL bits must be set. The device
clock must also be configured for one of the primary
modes (EC, HS or XT); otherwise, if the ROSEL bit is
not also set, the oscillator on OSC1 and OSC2 will be
powered down when the device enters Sleep mode.
Clearing the ROSEL bit allows the reference output
frequency to change as the system clock changes
during any clock switches.
Reference Clock Output
drive
© 2009 Microchip Technology Inc.
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