ATMEGA324PA-PU Atmel, ATMEGA324PA-PU Datasheet - Page 146

MCU AVR 32KB FLASH 40PDIP

ATMEGA324PA-PU

Manufacturer Part Number
ATMEGA324PA-PU
Description
MCU AVR 32KB FLASH 40PDIP
Manufacturer
Atmel
Series
AVR® ATmegar

Specifications of ATMEGA324PA-PU

Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
32
Program Memory Size
32KB (16K x 16)
Program Memory Type
FLASH
Eeprom Size
1K x 8
Ram Size
2K x 8
Voltage - Supply (vcc/vdd)
1.8 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
40-DIP (0.600", 15.24mm)
Controller Family/series
AVR MEGA
No. Of I/o's
32
Eeprom Memory Size
1KB
Ram Memory Size
2KB
Cpu Speed
20MHz
Rohs Compliant
Yes
For Use With
ATSTK600 - DEV KIT FOR AVR/AVR32
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
16.7.3
8272A–AVR–01/10
Fast PWM Mode
The timing diagram for the CTC mode is shown in
(TCNT2) increases until a compare match occurs between TCNT2 and OCR2A, and then coun-
ter (TCNT2) is cleared.
Figure 16-5. CTC Mode, Timing Diagram
An interrupt can be generated each time the counter value reaches the TOP value by using the
OCF2A Flag. If the interrupt is enabled, the interrupt handler routine can be used for updating
the TOP value. However, changing TOP to a value close to BOTTOM when the counter is run-
ning 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 OCR2A is lower than the current
value of TCNT2, the counter will miss the compare match. The counter will then have to count to
its maximum value (0xFF) and wrap around starting at 0x00 before the compare match can
occur.
For generating a waveform output in CTC mode, the OC2A output can be set to toggle its logical
level on each compare match by setting the Compare Output mode bits to toggle mode
(COM2A1:0 = 1). The OC2A value will not be visible on the port pin unless the data direction for
the pin is set to output. The waveform generated will have a maximum frequency of f
f
equation:
The N variable represents the prescale factor (1, 8, 32, 64, 128, 256, or 1024).
As for the Normal mode of operation, the
counter counts from MAX to 0x00.
The fast Pulse Width Modulation or fast PWM mode (WGM22:0 = 3 or 7) provides a high fre-
quency PWM waveform generation option. The fast PWM differs from the other PWM option by
its single-slope operation. The counter counts from BOTTOM to TOP then restarts from BOT-
TOM. TOP is defined as 0xFF when WGM22:0 = 3, and OCR2A when MGM22:0 = 7. In non-
inverting Compare Output mode, the Output Compare (OC2x) is cleared on the compare match
between TCNT2 and OCR2x, and set at BOTTOM. In inverting Compare Output mode, the out-
put is set on compare match and cleared at BOTTOM. Due to the single-slope operation, the
operating frequency of the fast PWM mode can be twice as high as the phase correct PWM
mode that uses dual-slope operation. This high frequency makes the fast PWM mode well suited
clk_I/O
164A/164PA/324A/324PA/644A/644PA/1284/1284P
/2 when OCR2A is set to zero (0x00). The waveform frequency is defined by the following
TCNTn
OCnx
(Toggle)
Period
1
f
OCnx
2
=
TOV2
------------------------------------------------- -
2 N
3
Flag is set in the same timer clock cycle that the
f
(
clk_I/O
1
Table 16-5 on page
+
4
OCRnx
)
146. The counter value
OCnx Interrupt Flag Set
(COMnx1:0 = 1)
OC2A
146
=

Related parts for ATMEGA324PA-PU