ATMEGA64M1-15MZ Atmel, ATMEGA64M1-15MZ Datasheet - Page 121

• Manufacturer Part Number: ATMEGA64M1-15MZ
• Description: MCU AVR 64KB FLASH 3PSC 32-VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA64M1-15MZ

• Package / Case: 32-VQFN
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Speed: 16MHz
• Eeprom Size: 2K x 8
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 4K x 8
• Program Memory Size: 64KB (64K x 8)
• Data Converters: A/D 11x10b; D/A 1x10b
• Oscillator Type: Internal
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Connectivity: CAN, LIN, SPI, UART/USART
• Core Size: 8-Bit
• Processor Series: ATMEGA64x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT, ATADAPCAN01
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of I /o: -
• Lead Free Status / Rohs Status: Details

13.8.3
7647G–AVR–09/11
Fast PWM Mode
Figure 13-6. CTC Mode, Timing Diagram
An interrupt can be generated at each time the counter value reaches the TOP value by either
using the OCFnA or ICFn Flag according to the register used to define the TOP value. If the
interrupt is enabled, the interrupt handler routine can be used for updating the TOP value.
However, changing the TOP to a value close to BOTTOM when the counter is running with
none or a low prescaler value must be done with care since the CTC mode does not have the
double buffering feature. If the new value written to OCRnA or ICRn is lower than the current
value of TCNTn, the counter will miss the compare match. The counter will then have to count
to its maximum value (0xFFFF) and wrap around starting at 0x0000 before the compare match
can occur. In many cases this feature is not desirable. An alternative will then be to use the
fast PWM mode using OCRnA for defining TOP (WGMn3:0 = 15) since the OCRnA then will
be double buffered.
For generating a waveform output in CTC mode, the OCnA output can be set to toggle its log-
ical level on each compare match by setting the Compare Output mode bits to toggle mode
(COMnA1:0 = 1). The OCnA value will not be visible on the port pin unless the data direction
for the pin is set to output (DDR_OCnA = 1). The waveform generated will have a maximum
frequency of f
defined by the following equation:
The N variable represents the prescaler factor (1, 8, 64, 256, or 1024).
As for the Normal mode of operation, the TOVn Flag is set in the same timer clock cycle that
the counter counts from MAX to 0x0000.
The fast Pulse Width Modulation or fast PWM mode (WGMn3:0 = 5, 6, 7, 14, or 15) provides a
high frequency PWM waveform generation option. The fast PWM differs from the other PWM
options by its single-slope operation. The counter counts from BOTTOM to TOP then restarts
from BOTTOM. In non-inverting Compare Output mode, the Output Compare (OCnx) is set on
the compare match between TCNTn and OCRnx, and cleared at TOP. In inverting Compare
Output mode output is cleared on compare match and set at TOP. Due to the single-slope
operation, the operating frequency of the fast PWM mode can be twice as high as the phase
correct and phase and frequency correct PWM modes that use dual-slope operation. This high
frequency makes the fast PWM mode well suited for power regulation, rectification, and DAC
applications. High frequency allows physically small sized external components (coils, capaci-
tors), hence reduces total system cost.
f
OCnA
TCNTn
OCnA
(Toggle)
Period
=
------------------------------------------------------- -
2
N
OC
n
A
f
clk_I/O
= f
1
+
1
clk_I/O
OCRnA
/2 when OCRnA is set to zero (0x0000). The waveform frequency is
2
Atmel ATmega16/32/64/M1/C1
3
4
OCnA Interrupt Flag Set
or ICFn Interrupt Flag Set
(Interrupt on TOP)
(COMnA1:0 = 1)
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