ATtiny461 Automotive Atmel Corporation, ATtiny461 Automotive Datasheet - Page 138

• Manufacturer Part Number: ATtiny461 Automotive
• Manufacturer: Atmel Corporation

Specifications of ATtiny461 Automotive

• Flash (kbytes): 4 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 16 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: 11
• 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): 256
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 150
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

138
ATtiny261/ATtiny461/ATtiny861
Table 17-1.
Note:
• Bit 3:2 – USICS1:0: Clock Source Select
These bits set the clock source for the USI Data Register and counter. The data output latch
ensures that the output is changed at the opposite edge of the sampling of the data input
(DI/SDA) when using external clock source (USCK/SCL). When software strobe or
Timer/Counter0 Compare Match clock option is selected, the output latch is transparent and
therefore the output is changed immediately. Clearing the USICS1:0 bits enables software
strobe option. When using this option, writing a one to the USICLK bit clocks both the USI Data
Register and the counter. For external clock source (USICS1 = 1), the USICLK bit is no longer
used as a strobe, but selects between external clocking and software clocking by the USITC
strobe bit.
Table 17-2 on page 139
clock source used for the USI Data Register and the 4-bit counter.
USIWM1
0
0
1
1
1. The DI and USCK pins are renamed to Serial Data (SDA) and Serial Clock (SCL) respectively
to avoid confusion between the modes of operation.
USIWM0 Description
Relations between USIWM1..0 and the USI Operation
0
1
0
1
Outputs, clock hold, and start detector disabled. Port pins operates as normal.
Three-wire mode. Uses DO, DI, and USCK pins.
The Data Output (DO) pin overrides the corresponding bit in the PORT Register in
this mode. However, the corresponding DDR bit still controls the data direction.
When the port pin is set as input the pins pull-up is controlled by the PORT bit.
The Data Input (DI) and Serial Clock (USCK) pins do not affect the normal port
operation. When operating as master, clock pulses are software generated by
toggling the PORT Register, while the data direction is set to output. The USITC
bit in the USICR Register can be used for this purpose.
Two-wire mode. Uses SDA (DI) and SCL (USCK) pins
The Serial Data (SDA) and the Serial Clock (SCL) pins are bi-directional and uses
open-collector output drives. The output drivers are enabled by setting the
corresponding bit for SDA and SCL in the DDR Register.
When the output driver is enabled for the SDA pin, the output driver will force the
line SDA low if the output of the USI Data Register or the corresponding bit in the
PORT Register is zero. Otherwise the SDA line will not be driven (i.e., it is
released). When the SCL pin output driver is enabled the SCL line will be forced
low if the corresponding bit in the PORT Register is zero, or by the start detector.
Otherwise the SCL line will not be driven.
The SCL line is held low when a start detector detects a start condition and the
output is enabled. Clearing the Start Condition Flag (USISIF) releases the line.
The SDA and SCL pin inputs is not affected by enabling this mode. Pull-ups on the
SDA and SCL port pin are disabled in Two-wire mode.
Two-wire mode. Uses SDA and SCL pins.
Same operation as for the Two-wire mode described above, except that the SCL
line is also held low when a counter overflow occurs, and is held low until the
Counter Overflow Flag (USIOIF) is cleared.
shows the relationship between the USICS1..0 and USICLK setting and
(1)
.
7753F–AVR–01/11