ATA8741 ATMEL Corporation, ATA8741 Datasheet - Page 102

• Manufacturer Part Number: ATA8741
• Manufacturer: ATMEL Corporation

102
ATA8741
Note:
Table 20-4
rect PWM mode.
Table 20-7.
Note:
• Bits 3, 2 – Res: Reserved Bits
These bits are reserved bits in the ATtiny24/44/84 and will always read as zero.
• Bits 1:0 – WGM01:0: Waveform Generation Mode
Combined with the WGM02 bit found in the TCCR0B Register, these bits control the counting
sequence of the counter, the source for maximum (TOP) counter value, and what type of wave-
form generation to be used, see
Timer/Counter unit are: Normal mode (counter), Clear Timer on Compare Match (CTC) mode,
and two types of Pulse Width Modulation (PWM) modes (see
Table 20-8.
Note:
Mode
COM0A1
0
1
2
3
4
5
6
7
0
0
1
1
1. A special case occurs when OCR0B equals TOP and COM0B1 is set. In this case, the Com-
1. A special case occurs when OCR0B equals TOP and COM0B1 is set. In this case, the Com-
1. MAX
WGM2
pare Match is ignored, but the set or clear is done at BOTTOM. See
page 95
pare Match is ignored, but the set or clear is done at TOP. See
page 97
BOTTOM = 0x00
shows the COM0B1:0 bit functionality when the WGM02:0 bits are set to phase cor-
0
0
0
0
1
1
1
1
Compare Output Mode, Phase Correct PWM Mode
Waveform Generation Mode Bit Description
COM0A0
for more details.
for more details.
= 0xFF
WGM1
0
1
0
1
0
0
1
1
0
0
1
1
Description
Normal port operation, OC0B disconnected.
Reserved
Clear OC0B on Compare Match when up-counting. Set OC0B on
Compare Match when down-counting.
Set OC0B on Compare Match when up-counting. Clear OC0B on
Compare Match when down-counting.
WGM0
Table 20-8 on page
0
1
0
1
0
1
0
1
Timer/Counter
Mode of
Operation
Normal
PWM, Phase
Correct
CTC
Fast PWM
Reserved
PWM, Phase
Correct
Reserved
Fast PWM
102. Modes of operation supported by the
OCRA
OCRA
OCRA
0xFF
0xFF
0xFF
“Modes of Operation” on page
TOP
–
–
(1)
“Phase Correct PWM Mode” on
Immediate
Immediate
Update of
BOTTOM
BOTTOM
OCRx at
“Fast PWM Mode” on
TOP
TOP
–
–
9140B–INDCO–07/09
TOV Flag
BOTTOM
BOTTOM
Set on
MAX
MAX
MAX
TOP
–
–
(1)
94).