Datasheet

168
7766F–AVR–11/10
ATmega16/32U4
• Bit 1 - FOC4D: Force Output Compare Match 4D
The FOC4D bit is only active when the PWM4D bit specify a non-PWM mode.
Writing a logical one to this bit forces a change in the Waveform Output (OCW4D) and the Out-
put Compare pin (OC4D) according to the values already set in COM4D1 and COM4D0. If
COM4D1 and COM4D0 written in the same cycle as FOC4D, the new settings will be used. The
Force Output Compare bit can be used to change the output pin value regardless of the timer
value. The automatic action programmed in COM4D1 and COM4D0 takes place as if a compare
match had occurred, but no interrupt is generated. The FOC4D bit is always read as zero.
• Bit 0 - PWM4D: Pulse Width Modulator D Enable
When set (one) this bit enables PWM mode based on comparator OCR4D.
15.12.4 TCCR4D – Timer/Counter4 Control Register D
• Bit 7 - FPIE4: Fault Protection Interrupt Enable
Setting this bit (to one) enables the Fault Protection Interrupt.
• Bit 6– FPEN4: Fault Protection Mode Enable
Setting this bit (to one) activates the Fault Protection Mode.
• Bit 5 – FPNC4: Fault Protection Noise Canceler
Setting this bit activates the Fault Protection Noise Canceler. When the noise canceler is acti-
vated, the input from the Fault Protection Pin (INT0) is filtered. The filter function requires four
successive equal valued samples of the INT0 pin for changing its output. The Fault Protection is
therefore delayed by four Oscillator cycles when the noise canceler is enabled.
• Bit 4 – FPES4: Fault Protection Edge Select
This bit selects which edge on the Fault Protection pin (INT0) is used to trigger a fault event.
When the FPES4 bit is written to zero, a falling (negative) edge is used as trigger, and when the
FPES4 bit is written to one, a rising (positive) edge will trigger the fault.
Table 15-18. Compare Output Mode, Phase and Frequency Correct PWM Mode
COM4D1..0 OCW4D Behavior OC4D Pin OC4D Pin
00 Normal port operation. Disconnected Disconnected
01
Cleared on Compare Match when up-counting.
Set on Compare Match when down-counting.
Connected Connected
10
Cleared on Compare Match when up-counting.
Set on Compare Match when down-counting.
Connected Disconnected
11
Set on Compare Match when up-counting.
Cleared on Compare Match when down-counting.
Connected Disconnected
Bit 76543210
FPIE4 FPEN4 FPNC4 FPES4 FPAC4 FPF4 WGM41 WGM40 TCCR4D
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 00000000