ATtiny43U Atmel Corporation, ATtiny43U Datasheet - Page 34

• 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

7.4.6
7.5
7.5.1
34
Register Description
ATtiny43U
Port Pins
MCUCR – MCU Control Register
When entering a sleep mode, all port pins should be configured to use minimum power. The
most important thing is then to ensure that no pins drive resistive loads. In sleep modes where
both the I/O clock (clk
will be disabled. This ensures that no power is consumed by the input logic when not needed. In
some cases, the input logic is needed for detecting wake-up conditions, and it will then be
enabled. See the section
which pins are enabled. If the input buffer is enabled and the input signal is left floating or has an
analog signal level close to V
For analog input pins, the digital input buffer should be disabled at all times. An analog signal
level close to V
input buffers can be disabled by writing to the Digital Input Disable Register (DIDR0). See
“DIDR0 – Digital Input Disable Register 0” on page 130
The MCU Control Register contains control bits for power management.
• Bit 7 – BODS: BOD Sleep
The BODS bit must be written to logic one in order to turn off BOD during sleep, see
on page
BODSE in MCUCR. To disable BOD in relevant sleep modes, both BODS and BODSE must first
be set to one. Then, to set the BODS bit, BODS must be set to one and BODSE must be set to
zero within four clock cycles.
The BODS bit is active three clock cycles after it is set. A sleep instruction must be executed
while BODS is active in order to turn off the BOD for the actual sleep mode. The BODS bit is
automatically cleared after three clock cycles.
• Bit 5 – SE: Sleep Enable
The SE bit must be written to logic one to make the MCU enter the sleep mode when the SLEEP
instruction is executed. To avoid the MCU entering the sleep mode unless it is the programmer’s
purpose, it is recommended to write the Sleep Enable (SE) bit to one just before the execution of
the SLEEP instruction and to clear it immediately after waking up.
• Bits 4, 3 – SM[1:0]: Sleep Mode Select Bits 2:0
These bits select between the three available sleep modes as shown in
Table 7-2.
Bit
0x35 (0x55)
Read/Write
Initial Value
SM1
0
31. Writing to the BODS bit is controlled by a timed sequence and an enable bit,
Sleep Mode Select
CC
BODS
R/W
7
0
/2 on an input pin can cause significant current even in active mode. Digital
I/O
) and the ADC clock (clk
PUD
R/W
SM0
6
0
“Digital Input Enable and Sleep Modes” on page 66
0
CC
/2, the input buffer will use excessive power.
R/W
SE
5
0
Sleep Mode
Idle
SM1
R/W
4
0
ADC
) are stopped, the input buffers of the device
SM0
R/W
3
0
for details.
BODSE
R/W
2
0
ISC01
R/W
1
0
Table 7-2
ISC00
R/W
0
0
for details on
8048B–AVR–03/09
below.
Table 7-1
MCUCR