ATMEGA88V-10AU Atmel, ATMEGA88V-10AU Datasheet - Page 140

• Manufacturer Part Number: ATMEGA88V-10AU
• Description: IC AVR MCU 8K 10MHZ 1.8V 32TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA88V-10AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 10MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 8KB (4K 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: 32-TQFP, 32-VQFP
• Processor Series: ATMEGA8x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 1 KB
• Interface Type: 2-Wire, SPI, USART, Serial
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 23
• Number Of Timers: 3 bit
• Operating Supply Voltage: 1.8 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• Package: 32TQFP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 10 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

17.2.1
17.2.2
17.3
17.4
140
Timer/Counter Clock Sources
Counter Unit
ATmega48/88/168
Registers
Definitions
The Timer/Counter (TCNT2) and Output Compare Register (OCR2A and OCR2B) are 8-bit reg-
isters. Interrupt request (shorten as Int.Req.) signals are all visible in the Timer Interrupt Flag
Register (TIFR2). All interrupts are individually masked with the Timer Interrupt Mask Register
(TIMSK2). TIFR2 and TIMSK2 are not shown in the figure.
The Timer/Counter can be clocked internally, via the prescaler, or asynchronously clocked from
the TOSC1/2 pins, as detailed later in this section. The asynchronous operation is controlled by
the Asynchronous Status Register (ASSR). The Clock Select logic block controls which clock
source he Timer/Counter uses to increment (or decrement) its value. The Timer/Counter is inac-
tive 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 Register (OCR2A and OCR2B) 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 (OC2A and
OC2B).
set the Compare Flag (OCF2A or OCF2B) 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
Table 17-1.
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
– Asynchronous Status Register” on page
“Timer/Counter Prescaler” on page
The main part of the 8-bit Timer/Counter is the programmable bi-directional counter unit.
17-2
BOTTOM
MAX
TOP
shows a block diagram of the counter and its surrounding environment.
See “Output Compare Unit” on page 141.
Definitions
T2
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 OCR2A Register. The assignment is depen-
dent on the mode of operation.
).
Table 17-1
are also used extensively throughout the section.
T2
151.
is by default equal to the MCU clock, clk
158. For details on clock sources and prescaler, see
for details. The compare match event will also
I/O
. When the AS2
2545S–AVR–07/10
“ASSR
Figure