ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 146

• 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

15.6
7766F–AVR–11/10
Compare Match Output Unit
The length of the counting period is user adjustable by selecting the dead time prescaler setting
by using the DTPS41:40 control bits, and selecting then the dead time value in I/O register DT4.
The DT4 register consists of two 4-bit fields, DT4H and DT4L that control the dead time periods
of the PWM output and its' complementary output separately in terms of the number of pres-
caled dead time generator clock cycles. Thus the rising edge of OC4x and OC4x can have
different dead time periods as the t
t
Figure 15-8. The Complementary Output Pair, COM4x1:0 = 1
OCWnx
OCnx
OCnx
(COMnx = 1)
The Compare Output Mode (COM4x1:0) bits have two functions. The Waveform Generator uses
the COM4x1:0 bits for defining the inverted or non-inverted Waveform Output (OCW4x) at the
next Compare Match. Also, the COM4x1:0 bits control the OC4x and OC4x pin output source.
Figure 15-9
I/O Registers, I/O bits, and I/O pins in the figure are shown in bold. Only the parts of the general
I/O Port Control Registers (DDR and PORT) that are affected by the COM4x1:0 bits are shown.
In Normal Mode (non-PWM) the Dead Time Generator is disabled and it is working like a syn-
chronizer: the Output Compare (OC4x) is delayed from the Waveform Output (OCW4x) by one
timer clock cycle. Whereas in Fast PWM Mode and in Phase and Frequency Correct PWM
Mode when the COM4x1:0 bits are set to “01” both the non-inverted and the inverted Output
Compare output are generated, and an user programmable Dead Time delay is inserted for
these complementary output pairs (OC4x and OC4x). The functionality in PWM modes is similar
to Normal mode when any other COM4x1:0 bit setup is used. When referring to the OC4x state,
the reference is for the Output Compare output (OC4x) from the Dead Time Generator, not the
OC4x pin. If a system reset occur, the OC4x is reset to “0”.
The general I/O port function is overridden by the Output Compare (OC4x / OC4x) from the
Dead Time Generator if either of the COM4x1:0 bits are set. However, the OC4x pin direction
(input or output) is still controlled by the Data Direction Register (DDR) for the port pin. The Data
Direction Register bit for the OC4x and OC4x pins (DDR_OC4x and DDR_OC4x) must be set as
output before the OC4x and OC4x values are visible on the pin. The port override function is
independent of the Output Compare mode.
The design of the Output Compare Pin Configuration logic allows initialization of the OC4x state
before the output is enabled. Note that some COM4x1:0 bit settings are reserved for certain
modes of operation. For Output Compare Pin Configurations refer to
Table 15-3 on page
non-overlap / falling edge
t
non-overlap / rising edge
shows a simplified schematic of the logic affected by the COM4x1:0 bit setting. The
is adjusted by the 4-bit DT4L value.
152,
Table 15-4 on page
t
non-overlap / falling edge
non-overlap / rising edge
154, and
is adjusted by the 4-bit DT4H value and the
Table 15-5 on page
ATmega16/32U4
Table 15-2 on page
155.
151,
146