AT90PWM1 Atmel Corporation, AT90PWM1 Datasheet - Page 47

• Manufacturer Part Number: AT90PWM1
• Manufacturer: Atmel Corporation

Specifications of AT90PWM1

• Flash (kbytes): 8 Kbytes
• Pin Count: 24
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 19
• Ext Interrupts: 4
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 125
• Analog Comparators: 2
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 105
• 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: 1
• Pwm Channels: 7
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

9.1
9.1.1
9.1.2
4378C–AVR–09/08
Internal Voltage Reference
Voltage Reference Enable Signals and Start-up Time
Voltage Reference Characteristics
This bit is set if an External Reset occurs. The bit is reset by a Power-on Reset, or by writing a
logic zero to the flag.
• Bit 0 – PORF: Power-on Reset Flag
This bit is set if a Power-on Reset occurs. The bit is reset only by writing a logic zero to the flag.
To make use of the Reset flags to identify a reset condition, the user should read and then reset
the MCUSR as early as possible in the program. If the register is cleared before another reset
occurs, the source of the reset can be found by examining the reset flags.
AT90PWM1 features an internal bandgap reference. This reference is used for Brown-out
Detection. It can also be used as a voltage reference for the DAC and/or the ADC, and can be
used as analog input for the analog comparators. In order to use the internal Vref, it is necessary
to configure it thanks to the REFS1 and REFS0 bits in the ADMUX register and to set an analog
feature which requires it.
The voltage reference has a start-up time that may influence the way it should be used. The
start-up time is given in
reference is on during the following situations:
1. When the BOD is enabled (by programming the BODLEVEL [2..0] Fuse).
2. When the bandgap reference is connected to the Analog Comparator (by setting the
3. When the ADC is enabled.
4. When the DAC is enabled.
Thus, when the BOD is not enabled, after setting the ACBG bit or enabling the ADC or the DAC,
the user must always allow the reference to start up before the output from the Analog Compar-
ator or ADC or DAC is used. To reduce power consumption in Power-down mode, the user can
avoid the three conditions above to ensure that the reference is turned off before entering
Power-down mode.
Table 9-4.
Note:
Symbol
V
ACBG bit in ACSR).
t
I
BG
BG
BG
1. Values are guidelines only.
Parameter
Bandgap reference voltage
Bandgap reference start-up time
Bandgap reference current
consumption
Internal Voltage Reference Characteristics
Table
9-4. To save power, the reference is not always turned on. The
Condition
(1)
Min.
Typ.
1.1
40
15
AT90PWM1
Max.
Units
µA
µs
V
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