ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 145

• Manufacturer Part Number: ATmega32U4
• Manufacturer: Atmel Corporation

Specifications of ATmega32U4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 14
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 26
• Ext Interrupts: 13
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 3.3
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 12
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

15.5
7766F–AVR–11/10
Dead Time Generator
The Dead Time Generator is provided for the Timer/Counter4 PWM output pairs to allow driving
external power control switches safely. The Dead Time Generator is a separate block that can
be used to insert dead times (non-overlapping times) for the Timer/Counter4 complementary
output pairs OC4x and OC4x when the PWM mode is enabled and the COM4x1:0 bits are set to
“01”. The sharing of tasks is as follows: the Waveform Generator generates the Waveform Out-
put (OCW4x) and the Dead Time Generator generates the non-overlapping PWM output pair
from the Waveform Output. Three Dead Time Generators are provided, one for each PWM out-
put. The non-overlap time is adjustable and the PWM output and it’s complementary output are
adjusted separately, and independently for both PWM outputs.
Figure 15-6. Output Compare Unit, Block Diagram
The Dead Time Generation is based on the 4-bit down counters that count the dead time, as
shown in
can divide the Timer/Counter4 clock (PCK or CK) by 1, 2, 4 or 8. This provides for large range of
dead times that can be generated. The prescaler is controlled by two control bits DTPS41..40.
The block has also a rising and falling edge detector that is used to start the dead time counting
period. Depending on the edge, one of the transitions on the rising edges, OC4x or OC4x is
delayed until the counter has counted to zero. The comparator is used to compare the counter
with zero and stop the dead time insertion when zero has been reached. The counter is loaded
with a 4-bit DT4H or DT4L value from DT4 I/O register, depending on the edge of the Waveform
Output (OCW4x) when the dead time insertion is started. The Output Compare Output are
delayed by one timer clock cycle at minimum from the Waveform Output when the Dead Time is
adjusted to zero. The outputs OC4x and OC4x are inverted, if the PWM Inversion Mode bit
PWM4X is set. This will also cause both outputs to be high during the dead time.
Figure 15-7. Dead Time Generator
CK OR PCK
OCWnx
CLOCK
bottom
FOCn
top
TCCRnB REGISTER
Figure
PRE-SCALER
DEAD TIME
15-7. There is a dedicated prescaler in front of the Dead Time Generator that
PWMnx
Waveform Generator
WGMn0
CLOCK CONTROL
COMnx
CK OR PCK
OCWnx
CLOCK
DTn I/O REGISTER
4-BIT COUNTER
COMPARATOR
DTPSn
Dead Time Generator
DATA BUS (8-bit)
DTnH
ATmega16/32U4
DTnL
OCnx
OCnx
PWMnX
PWMnX
OCnx
OCnx
pin
pin
OCnx
OCnx
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