ATtiny43U Atmel Corporation, ATtiny43U Datasheet - Page 38

• Manufacturer Part Number: ATtiny43U
• Manufacturer: Atmel Corporation

Specifications of ATtiny43U

• Flash (kbytes): 4 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 8 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 16
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 4
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.25
• Eeprom (bytes): 64
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 0.7 to 5.5
• Operating Voltage (vcc): 0.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

8.2.1
8.2.2
8.2.3
8.2.4
38
ATtiny43U
Stop Mode
Start Mode
Active Mode
Examples
The boost converter enters Stop Mode (see
input voltage ,V
natively, the boost converter enters Stop Mode when instructed by firmware to do so.
In this mode of operation the boost converter is not active and current consumption is decreased
to a minimum. This is in order to prevent battery discharge and to avoid battery damage.
The voltage at the converter output, V
voltage of the input pin, V
20-7 on page
and enters Start Mode.
The converter switches from Stop Mode to Start Mode (see
the input voltage, V
Alternatively, the boost converter switches from Active Mode to Start Mode when the output volt-
age drops below V
In this mode of operation the boost converter pumps up the V
duty cycle and high frequency, until it reaches V
All loads should be disconnected during this stage. The boost converter is designed to remain in
Start Mode for a short moment, but it is optimised to bring the microcontroller on line, only. If
there are additional loads connected to the V
voltage required to go into Active Mode.
The converter enters Active Mode of operation (see
output voltages are sufficiently high. This means that V
V
will exit Active Mode. Alternatively, firmware can force the boost converter to exit Active Mode
and enter Stop Mode.
In this mode of operation, the boost converter keeps V
page 159
The duty cycle is affected mainly by input voltage, V
By default, the boost converter operates in Active Regulated Mode but when load current drops
sufficiently low it will enter Active Low Current Mode, as explained in
Load Current”
output voltage regulation.
Figure 8-4
input voltage, V
converter enters Start Mode and output voltage, V
the converter exits Start Mode and goes into Active Mode. When output voltage exceeds the
power-on threshold V
troller is released from reset.
BOOST
. If input voltage drops below V
by constantly adjusting the duty cycle between energy charge and discharge phases.
illustrates operating modes and input and output voltages of the boost converter. As
159). When there is sufficient voltage at the input the converter exits Stop Mode
. In Active Low Current Mode current consumption is minimised on the expense of
BAT
BAT
, rises above V
BOOST
, is below the shutdown voltage, V
BAT
POT
, goes above the start voltage, V
.
(see
BAT
, and waits for it to rise above the start voltage, V
“System and Reset Characteristics” on page
START
CC
STOP
(see
, has no effect in this mode. The converter monitors the
or output voltage drops below V
Figure 8-3 on page 37
“Boost Converter Characteristics” on page
CC
BOOST
pin the boost converter may not reach the V
CC
Figure 8-3 on page
BAT
.
STOP
, begins to rise. At V
, load current, I
CC
BAT
START
(see
within limits given in
Figure 8-3 on page
is above V
CC
Table 20-7 on page
(see
voltage by switcing at a 50%
for modes of operation) when
Table 20-7 on page
LOAD
37) when both input and
START
“Output Voltage versus
, and temperature.
BOOST
BOOST
158) the microcon-
and V
START
37) as soon as
Table 20-7 on
output voltage
8048B–AVR–03/09
the converter
CC
159). Alter-
(see
is above
159) the
Table
159).
CC