AT90USB647-MU Atmel, AT90USB647-MU Datasheet - Page 164

• Manufacturer Part Number: AT90USB647-MU
• Description: MCU, 8BIT, 64K FLASH, USB, 64QFN
• Manufacturer: Atmel

Specifications of AT90USB647-MU

• Controller Family/series: AT90
• No. Of I/o's: 48
• Eeprom Memory Size: 2KB
• Ram Memory Size: 4KB
• Cpu Speed: 16MHz
• No. Of: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 64KB
• Oscillator Type: External, Internal
• Package: 64QFN EP
• Device Core: AVR
• Family Name: AT90
• Maximum Speed: 20 MHz
• Ram Size: 4 KB
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 48
• Interface Type: SPI/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 4
• Lead Free Status / Rohs Status: Details

15.8.3
15.8.4
15.8.5
164
AT90USB64/128
Timer/Counter Register – TCNT2
Output Compare Register A – OCR2A
Output Compare Register B – OCR2B
• Bit 3 – WGM22: Waveform Generation Mode
See the description in the
• Bit 2:0 – CS22:0: Clock Select
The three Clock Select bits select the clock source to be used by the Timer/Counter, see
15-8.
Table 15-8.
The Timer/Counter Register gives direct access, both for read and write operations, to the
Timer/Counter unit 8-bit counter. Writing to the TCNT2 Register blocks (removes) the Compare
Match on the following timer clock. Modifying the counter (TCNT2) while the counter is running,
introduces a risk of missing a Compare Match between TCNT2 and the OCR2x Registers.
The Output Compare Register A contains an 8-bit value that is continuously compared with the
counter value (TCNT2). A match can be used to generate an Output Compare interrupt, or to
generate a waveform output on the OC2A pin.
The Output Compare Register B contains an 8-bit value that is continuously compared with the
counter value (TCNT2). A match can be used to generate an Output Compare interrupt, or to
generate a waveform output on the OC2B pin.
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
CS22
0
0
0
0
1
1
1
1
7
TCNT2[7:0]
R/W
0
7
OCR2A[7:0]
R/W
0
7
OCR2B[7:0]
R/W
0
Clock Select Bit Description
CS21
0
0
1
1
0
0
1
1
6
R/W
0
6
R/W
0
6
R/W
0
“Timer/Counter Control Register A – TCCR2A” on page
CS20
5
R/W
0
5
R/W
0
5
R/W
0
0
1
0
1
0
1
0
1
4
R/W
0
4
R/W
0
4
R/W
0
Description
No clock source (Timer/Counter stopped).
clk
clk
clk
clk
clk
clk
clk
T2S
T2S
T2S
T2S
T2S
T
T
2
2
S
S
/256 (From prescaler)
/1024 (From prescaler)
/(No prescaling)
/8 (From prescaler)
/32 (From prescaler)
/64 (From prescaler)
/128 (From prescaler)
3
R/W
0
3
R/W
0
3
R/W
0
2
R/W
0
2
R/W
0
2
R/W
0
1
0
1
0
1
0
R/W
R/W
R/W
0
R/W
0
0
R/W
0
0
R/W
0
TCNT2
OCR2A
OCR2B
7593K–AVR–11/09
160.
Table