ATmega32 Atmel Corporation, ATmega32 Datasheet - Page 115

• Manufacturer Part Number: ATmega32
• Manufacturer: Atmel Corporation

Specifications of ATmega32

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 32
• Ext Interrupts: 3
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

Definitions
Timer/Counter
Clock Sources
Counter Unit
2503Q–AVR–02/11
The double buffered Output Compare Register (OCR2) is compared with the Timer/Counter
value at all times. The result of the compare can be used by the waveform generator to generate
a PWM or variable frequency output on the Output Compare Pin (OC2).
Unit” on page 116.
which can be used to generate an output compare interrupt request.
Many register and bit references in this document are written in general form. A lower case “n”
replaces the Timer/Counter number, in this case 2. However, when using the register or bit
defines in a program, the precise form must be used (that is, TCNT2 for accessing
Timer/Counter2 counter value and so on). The definitions in
throughout the document.
Table 49. Definitions
The Timer/Counter can be clocked by an internal synchronous or an external asynchronous
clock source. The clock source clk
bit in the ASSR Register is written to logic one, the clock source is taken from the Timer/Counter
Oscillator connected to TOSC1 and TOSC2. For details on asynchronous operation, see
chronous Status Register – ASSR” on page
“Timer/Counter Prescaler” on page
The main part of the 8-bit Timer/Counter is the programmable bi-directional counter unit.
54
Figure 54. Counter Unit Block Diagram
Signal description (internal signals):
BOTTOM
MAX
TOP
count
direction
clear
clk
top
shows a block diagram of the counter and its surrounding environment.
T2
DATA BUS
TCNTn
The counter reaches the BOTTOM when it becomes zero (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 OCR2 Register. The
assignment is dependent on the mode of operation.
Increment or decrement TCNT2 by 1.
Selects between increment and decrement.
Clear TCNT2 (set all bits to zero).
Timer/Counter clock.
Signalizes that TCNT2 has reached maximum value.
for details. The compare match event will also set the Compare Flag (OCF2)
direction
count
clear
bottom
Control Logic
T2
131.
is by default equal to the MCU clock, clk
top
128. For details on clock sources and prescaler, see
TOVn
(Int.Req.)
clk
Tn
Prescaler
Table 49
ATmega32(L)
are also used extensively
Oscillator
See “Output Compare
T/C
I/O
clk
. When the AS2
I/O
TOSC2
TOSC1
“Asyn-
Figure
115