AT89LP428 Atmel Corporation, AT89LP428 Datasheet - Page 72

• Manufacturer Part Number: AT89LP428
• Manufacturer: Atmel Corporation

Specifications of AT89LP428

• Flash (kbytes): 4 Kbytes
• Max. Operating Frequency: 25 MHz
• Cpu: 8051-1C
• Max I/o Pins: 30
• Spi: 1
• Uart: 1
• Sram (kbytes): 0.75
• Eeprom (bytes): 512
• Self Program Memory: IAP
• Operating Voltage (vcc): 2.4 to 5.5
• Timers: 3
• Isp: SPI/OCD
• Watchdog: Yes

13.4.3
Table 13-6.
72
PHS
AT89LP428/828
Multi-Phasic PWM
000
001
010
011
100
2-0
Summary of Multi-Phasic Modes
Figure 13-11. Phase Correct Symmetrical (Center-Aligned) PWM
The PWM channels may be configured to provide multi-phasic alternating outputs by the PHS
bits in T2MOD. The AT89LP428/828 provides 1 out of 2, 1 out of 3, 1 out of 4 and 2 out of 4
phase modes (see
CCD are connected to a one-hot shift register that selectively enables and disables the outputs
(see
as if the compare value was set equal to TOP. The PHSD bit in T2MOD controls the direction of
the shift register. Example waveforms are shown in
multi-phasic PWM, the associated channels must be configured for PWM operation. Non-PWM
channels are not affected by multi-phasic operation. However, their locations in the shift register
are maintained such that some periods in the PWM outputs may not have any pulses as shown
in
The PHS
PHSD are allowed at any time. Note that channels C and D in 1:2 phase mode and channel D in
1:3 phase mode operate normally.
{RCAP2H,RCA2L}
Figure
Figure
{CCxH,CCxL}
Non-Inverted
Mode
2-0
13-14.
Inverted
1:2
1:3
1:4
2:4
Off
13-12). Compare points on disabled channels are blocked from toggling the output
bits may only be modified when the timer is not operational (TR2 = 0). Updates to
CCx
Table
13-6). In Multi-phasic mode, the PWM outputs on CCA, CCB, CCC and
A
→ → → → → → →
B
A
→ → → → →
C
C
CP/RL2 = 0, T2CM
B
A
A
PHSD = 0
Normal Operation (all channels active at all times)
→ → →
→ → →
→ → →
C
D
D
B
B
A
A
A
C
A
B
B
B
B
D
C
C
1-0
= 11B, DCEN = 0
Figure 13-13 on page
D
Behavior
D
→ → → → → → →
C
C
→ → → → →
D
B
B
B
B
PHSD = 1
→ → →
→ → →
→ → →
C
A
A
A
A
73. In order to use
B
C
B
D
D
3654A–MICRO–8/09
Duty Cycle Updated
A
B
A
C
C
A
B
A
2-0