ATMEGA164PA-AU Atmel, ATMEGA164PA-AU Datasheet - Page 95

• Manufacturer Part Number: ATMEGA164PA-AU
• Description: MCU AVR 16KB FLASH 20MHZ 44TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA164PA-AU

• 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: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K 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: 44-TQFP, 44-VQFP
• Cpu Family: ATmega
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 20MHz
• Interface Type: 2-Wire/SPI/USART
• Total Internal Ram Size: 1KB
• # I/os (max): 32
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 2.5/3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 1.8V
• On-chip Adc: 8-chx10-bit
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 44
• Package Type: TQFP
• Package: 44TQFP
• Family Name: ATmega
• Maximum Speed: 20 MHz
• Operating Supply Voltage: 2.5|3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

14.2.2
14.3
14.4
8272A–AVR–01/10
Timer/Counter Clock Sources
Counter Unit
Definitions
uses to increment (or decrement) its value. The Timer/Counter is inactive when no clock source
is selected. The output from the Clock Select logic is referred to as the timer clock (clk
The double buffered Output Compare Registers (OCR0A and OCR0B) are compared with the
Timer/Counter value at all times. The result of the compare can be used by the Waveform Gen-
erator to generate a PWM or variable frequency output on the Output Compare pins (OC0A and
OC0B).
Compare Flag (OCF0A or OCF0B) which can be used to generate an Output Compare interrupt
request.
Many register and bit references in this section are written in general form. A lower case “n”
replaces the Timer/Counter number, in this case 0. A lower case “x” replaces the Output Com-
pare Unit, in this case Compare Unit A or Compare Unit B. However, when using the register or
bit defines in a program, the precise form must be used, i.e., TCNT0 for accessing
Timer/Counter0 counter value and so on.
The definitions in
Table 14-1.
The Timer/Counter can be clocked by an internal or an external clock source. The clock source
is selected by the Clock Select logic which is controlled by the Clock Select (CS02:0) bits
located in the Timer/Counter Control Register (TCCR0B). For details on clock sources and pres-
caler, see
The main part of the 8-bit Timer/Counter is the programmable bi-directional counter unit.
14-2
Figure 14-2. Counter Unit Block Diagram
Signal description (internal signals):
164A/164PA/324A/324PA/644A/644PA/1284/1284P
BOTTOM
MAX
TOP
shows a block diagram of the counter and its surroundings.
See Section “14.5” on page 96.
”Timer/Counter Prescaler” on page
Definitions
DATA BUS
The counter reaches the BOTTOM when it becomes 0x00.
The counter reaches its MAXimum when it becomes 0xFF (decimal 255).
The counter reaches the TOP when it becomes equal to the highest value in the
count sequence. The TOP value can be assigned to be the fixed value 0xFF
(MAX) or the value stored in the OCR0A Register. The assignment is depen-
dent on the mode of operation.
TCNTn
Table 14-1
are also used extensively throughout the document.
direction
count
clear
bottom
for details. The Compare Match event will also set the
Control Logic
153.
top
TOVn
(Int.Req.)
clk
Tn
Clock Select
( From Prescaler )
Detector
Edge
Tn
T0
).
Figure
95