ATMEGA644A-PU Atmel, ATMEGA644A-PU Datasheet - Page 133

IC MCU AVR 64K FLASH 40PDIP

ATMEGA644A-PU

Manufacturer Part Number
ATMEGA644A-PU
Description
IC MCU AVR 64K FLASH 40PDIP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA644A-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
64KB (32K x 16)
Program Memory Type
FLASH
Eeprom Size
2K x 8
Ram Size
4K 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)
Processor Series
ATmega
Core
AVR
Data Bus Width
8 bit
Data Ram Size
4 KB
Interface Type
JTAG, TWI, SPI, USART
Maximum Clock Frequency
20 MHz
Number Of Programmable I/os
32
Number Of Timers
3
Operating Supply Voltage
3.3 V
Maximum Operating Temperature
+ 85 C
Mounting Style
Through Hole
Minimum Operating Temperature
- 40 C
Operating Temperature Range
- 40 C to + 85 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
15.11 Register Description
15.11.1
8272A–AVR–01/10
TCCR1A – Timer/Counter1 Control Register A
Figure 15-13. Timer/Counter Timing Diagram, with Prescaler (f
• Bit 7:6 – COMnA1:0: Compare Output Mode for Channel A
• Bit 5:4 – COMnB1:0: Compare Output Mode for Channel B
The COMnA1:0 and COMnB1:0 control the Output Compare pins (OCnA and OCnB respec-
tively) behavior. If one or both of the COMnA1:0 bits are written to one, the OCnA output
overrides the normal port functionality of the I/O pin it is connected to. If one or both of the
COMnB1:0 bit are written to one, the OCnB output overrides the normal port functionality of the
I/O pin it is connected to. However, note that the Data Direction Register (DDR) bit correspond-
ing to the OCnA or OCnB pin must be set in order to enable the output driver.
When the OCnA or OCnB is connected to the pin, the function of the COMnx1:0 bits is depen-
dent of the WGMn3:0 bits setting.
when the WGMn3:0 bits are set to a Normal or a CTC mode (non-PWM).
Table 15-2.
164A/164PA/324A/324PA/644A/644PA/1284/1284P
Bit
(0x80)
Read/Write
Initial Value
COMnA1/COMnB1
and ICF n
(PC and PFC PWM)
TOVn
(CTC and FPWM)
(Update at TOP)
0
0
1
1
TCNTn
TCNTn
OCRnx
(clk
as TOP)
clk
clk
I/O
(FPWM)
I/O
Tn
/8)
(if used
COM1A1
Compare Output Mode, non-PWM
R/W
7
0
COM1A0
COMnA0/COMnB0
R/W
6
0
TOP - 1
TOP - 1
Old OCRnx Value
0
1
0
1
COM1B1
Table 15-2 on page 133
R/W
5
0
COM1B0
R/W
4
0
Description
Normal port operation, OCnA/OCnB disconnected.
Toggle OCnA/OCnB on Compare Match.
Clear OCnA/OCnB on Compare Match (Set output to
low level).
Set OCnA/OCnB on Compare Match (Set output to
high level).
TOP
TOP
R
3
0
shows the COMnx1:0 bit functionality
BOTTOM
TOP - 1
clk_I/O
R
2
0
New OCRnx Value
/8)
WGM11
R/W
1
0
BOTTOM + 1
TOP - 2
WGM10
R/W
0
0
TCCR1A
133

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