AT90CAN128-16AE ATMEL Corporation, AT90CAN128-16AE Datasheet - Page 154

• Manufacturer Part Number: AT90CAN128-16AE
• Description: 8-bit Avr Microcontroller With 128K Bytes of Isp Flash And CAN Controller.flash (Kbytes) 128 Vcc (V) 2.7-5.5 EEPROM (Kbytes) 4 SRAM (bytes) 4K CAN (mess. Obj.) 15
• Manufacturer: ATMEL Corporation

Timer/Counter2 Register –
TCNT2
154
AT90CAN128
Note:
Table 69 shows the COM21:0 bit functionality when the WGM21:0 bits are set to phase
correct PWM mode.
Table 69. Compare Output Mode, Phase Correct PWM Mode
Note:
• Bit 2:0 – CS22:0: Clock Select
The three Clock Select bits select the clock source to be used by the Timer/Counter, see
Table 70.
Table 70. Clock Select Bit Description
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 OCR2A Register.
Bit
Read/Write
Initial Value
COM2A1
CS22
0
0
0
0
1
1
1
1
0
0
1
1
1. A special case occurs when OCR2A equals TOP and COM2A1 is set. In this case,
1. A special case occurs when OCR2A equals TOP and COM2A1 is set. In this case,
the compare match is ignored, but the set or clear is done at TOP. See “Fast PWM
Mode” on page 148 for more details.
the compare match is ignored, but the set or clear is done at TOP. See “Phase Cor-
rect PWM Mode” on page 149 for more details.
R/W
COM2A0
7
0
CS21
0
0
1
1
0
0
1
1
0
1
0
1
R/W
6
0
Description
Normal port operation, OC2A disconnected.
Reserved
Clear OC2A on compare match when up-counting.
Set OC2A on compare match when downcounting.
Set OC2A on compare match when up-counting.
Clear OC2A on compare match when downcounting.
CS20
R/W
0
1
0
1
0
1
0
1
5
0
R/W
Description
No clock source (Timer/Counter stopped).
clk
clk
clk
clk
clk
clk
clk
4
0
TCNT2[7:0]
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)
R/W
3
0
R/W
2
0
(1)
R/W
1
0
R/W
0
0
4250C–CAN–03/04
TCNT2