at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 152

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

14.5.2.1
152
AT90PWM81
Four Ramp Mode
The waveform frequency is defined by the following equation:
In Four Ramp mode, each time in a cycle has its own definition
Figure 14-4.
The input clock of PSCR is given by CLKPSC.
PSCOUTr0 and PSCOUTr1 signals are defined by On-Time 0, Dead-Time 0, On-Time 1 and Dead-Time
1 values with :
On-Time 0 = OCRrRAH/L * 1/Fclkpsc
On-Time 1 = OCRrRBH/L * 1/Fclkpsc
Dead-Time 0 = (OCRrSAH/L + 2) * 1/Fclkpsc
Dead-Time 1 = (OCRrSBH/L + 2) * 1/Fclkpsc
Note:
PSC Counter
PSCOUTn0
PSCOUTn1
Minimal value for Dead-Time 0 and Dead-Time 1 = 2 * 1/Fclkpsc
OCRnSA
0
PSCr0 & PSCr1 Basic Waveforms in Four Ramp mode
Dead-Time 0
f
PSCn
=
On-Time 0
----------------------------- -
PSCnCycle
PSC Cycle
1
OCRnRA
=
-------------------------------------------------------------------- -
(
0
OT0
OCRnSB
Dead-Time 1
+
OT1
f
CLK_PSCn
+
DT0
On-Time 1
OCRnRB
+
DT1
)
7734M–AVR–03/10