ATtiny40 Atmel Corporation, ATtiny40 Datasheet - Page 124

• Manufacturer Part Number: ATtiny40
• Manufacturer: Atmel Corporation

Specifications of ATtiny40

• Flash (kbytes): 4 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 12 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: Yes
• Max I/o Pins: 18
• Ext Interrupts: 18
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 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): 0.25
• Self Program Memory: NO
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 2
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

124
ATtiny40
Low periods: Longer than 2 CPU clock cycles.
High periods: Longer than 2 CPU clock cycles.
When the SPI is enabled, the data direction of the MOSI, MISO, SCK, and SS pins is overridden
according to
“Alternate Port Functions” on page
Table 16-1.
Note:
The following code examples show how to initialize the SPI as a Master and how to perform a
simple transmission. DDR_SPI in the examples must be replaced by the actual Data Direction
Register controlling the SPI pins. DD_MOSI, DD_MISO and DD_SCK must be replaced by the
actual data direction bits for these pins. E.g. if MOSI is placed on pin PB5, replace DD_MOSI
with DDB5 and DDR_SPI with DDRB.
Assembly Code Example
MOSI
MISO
SCK
SPI_MasterInit:
SPI_MasterTransmit:
Wait_Transmit:
Pin
SS
; Set MOSI and SCK output, all others input
ldi
out
; Enable SPI, Master, set clock rate fck/16
ldi
out
ret
; Start transmission of data (r16)
out
; Wait for transmission complete
in
sbrsr16, SPIF
rjmp Wait_Transmit
ret
See
direction of the user defined SPI pins.
“Alternate Functions of Port B” on page 57
Table 16-1 on page
r17,(1<<DD_MOSI)|(1<<DD_SCK)
DDR_SPI,r17
r17,(1<<SPE)|(1<<MSTR)|(1<<SPR0)
SPCR,r17
SPDR,r16
r16, SPSR
SPI Pin Overrides
Direction, Master SPI
User Defined
Input
User Defined
User Defined
(1)
124. For more details on automatic port overrides, refer to
52.
for a detailed description of how to define the
Direction, Slave SPI
Input
User Defined
Input
Input
8263A–AVR–08/10