DSPIC33FJ128MC706-I/PT Microchip Technology Inc., DSPIC33FJ128MC706-I/PT Datasheet - Page 179

• Manufacturer Part Number: DSPIC33FJ128MC706-I/PT
• Description: 16 BIT MCU/DSP 64LD 40MIPS 128KB FLASH
• Manufacturer: Microchip Technology Inc.
• Type: DSPr

Specifications of DSPIC33FJ128MC706-I/PT

• A/d Inputs: 16-Channels, 12-Bit
• Comparators: 8
• Cpu Speed: 40 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 53
• Interface: CAN/I2C/SPI/UART
• Ios: 53
• Memory Type: Flash
• Number Of Bits: 16
• Package Type: 64-pin TQFP
• Programmable Memory: 128K Bytes
• Ram Size: 16K Bytes
• Timers: 9-16-bit, 4-32-bit
• Voltage, Range: 3-3.6
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

15.1
The PWM time base is provided by a 15-bit timer with
a prescaler and postscaler. The time base is accessible
via the PTMR SFR. PTMR<15> is a read-only status
bit, PTDIR, that indicates the present count direction of
the PWM time base. If PTDIR is cleared, PTMR is
counting upwards. If PTDIR is set, PTMR is counting
downwards. The PWM time base is configured via the
PTCON SFR. The time base is enabled/disabled by
setting/clearing the PTEN bit in the PTCON SFR.
PTMR is not cleared when the PTEN bit is cleared in
software.
The PTPER SFR sets the counting period for PTMR.
The user must write a 15-bit value to PTPER<14:0>.
When the value in PTMR<14:0> matches the value in
PTPER<14:0>, the time base will either reset to ‘0’ or
reverse the count direction on the next occurring clock
cycle. The action taken depends on the operating
mode of the time base.
The PWM time base can be configured for four different
modes of operation:
• Free-Running mode
• Single-Shot mode
• Continuous Up/Down Count mode
• Continuous Up/Down Count mode with interrupts
These four modes are selected by the PTMOD<1:0>
bits in the PTCON SFR. The Up/Down Count modes
support center-aligned PWM generation. The Single-
Shot mode allows the PWM module to support pulse
control of certain Electronically Commutative Motors
(ECMs).
The interrupt signals generated by the PWM time base
depend on the mode selection bits (PTMOD<1:0>) and
the postscaler bits (PTOPS<3:0>) in the PTCON SFR.
© 2006 Microchip Technology Inc.
Note:
for double updates
PWM Time Base
If the PWM Period register is set to
0x0000, the timer will stop counting and
the interrupt and Special Event Trigger will
not be generated, even if the special event
value is also 0x0000. The module will not
update the PWM Period register if it is
already at 0x0000; therefore, the user
must disable the module in order to update
the PWM Period register.
Preliminary
15.1.1
In Free-Running mode, the PWM time base counts
upwards until the value in the PWM Time Base Period
register (PTPER) is matched. The PTMR register is
reset on the following input clock edge, and the time
base will continue to count upwards as long as the
PTEN bit remains set.
When the PWM time base is in the Free-Running mode
(PTMOD<1:0> = 00), an interrupt event is generated
each time a match with the PTPER register occurs and
the PTMR register is reset to zero. The postscaler
selection bits may be used in this mode of the timer to
reduce the frequency of the interrupt events.
15.1.2
In Single-Shot mode, the PWM time base begins
counting upwards when the PTEN bit is set. When the
value in the PTMR register matches the PTPER regis-
ter, the PTMR register will be reset on the following
input clock edge, and the PTEN bit will be cleared by
the hardware to halt the time base.
When the PWM time base is in the Single-Shot mode
(PTMOD<1:0> = 01), an interrupt event is generated
when a match with the PTPER register occurs. The
PTMR register is reset to zero on the following input
clock edge and the PTEN bit is cleared. The postscaler
selection bits have no effect in this mode of the timer.
15.1.3
In the Continuous Up/Down Count modes, the PWM
time base counts upwards until the value in the PTPER
register is matched. The timer will begin counting
downwards on the following input clock edge. The
PTDIR bit in the PTMR SFR is read-only and indicates
the counting direction. The PTDIR bit is set when the
timer counts downwards.
In the Up/Down Count mode (PTMOD<1:0> = 10), an
interrupt event is generated each time the value of the
PTMR register becomes zero and the PWM time base
begins to count upwards. The postscaler selection bits
may be used in this mode of the timer to reduce the
frequency of the interrupt events.
FREE-RUNNING MODE
SINGLE-SHOT MODE
CONTINUOUS UP/DOWN COUNT
MODES
dsPIC33F
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