ATtiny2313 Atmel Corporation, ATtiny2313 Datasheet - Page 145

• Manufacturer Part Number: ATtiny2313
• Manufacturer: Atmel Corporation

Specifications of ATtiny2313

• Flash (kbytes): 2 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 4
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 18
• Ext Interrupts: 18
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: YES
• 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: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

USI Status Register –
USISR
USI Control Register –
USICR
2543L–AVR–08/10
The Status Register contains interrupt flags, line status flags and the counter value.
• Bit 7 – USISIF: Start Condition Interrupt Flag
When Two-wire mode is selected, the USISIF flag is set (to one) when a start condition is
detected. When output disable mode or Three-wire mode is selected and (USICSx = 0b11 &
USICLK = 0) or (USICS = 0b10 & USICLK = 0), any edge on the SCK pin sets the flag.
An interrupt will be generated when the flag is set while the USISIE bit in USICR and the Global
Interrupt Enable Flag are set. The flag will only be cleared by writing a logical one to the USISIF
bit. Clearing this bit will release the start detection hold of USCL in Two-wire mode.
A start condition interrupt will wake-up the processor from all sleep modes.
• Bit 6 – USIOIF: Counter Overflow Interrupt Flag
This flag is set (one) when the 4-bit counter overflows (i.e., at the transition from 15 to 0). An
interrupt will be generated when the flag is set while the USIOIE bit in USICR and the Global
Interrupt Enable Flag are set. The flag will only be cleared if a one is written to the USIOIF bit.
Clearing this bit will release the counter overflow hold of SCL in Two-wire mode.
A counter overflow interrupt will wake-up the processor from Idle sleep mode.
• Bit 5 – USIPF: Stop Condition Flag
When Two-wire mode is selected, the USIPF flag is set (one) when a stop condition is detected.
The flag is cleared by writing a one to this bit. Note that this is not an interrupt flag. This signal is
useful when implementing Two-wire bus master arbitration.
• Bit 4 – USIDC: Data Output Collision
This bit is logical one when bit 7 in the Shift Register differs from the physical pin value. The flag
is only valid when Two-wire mode is used. This signal is useful when implementing Two-wire
bus master arbitration.
• Bits 3..0 – USICNT3..0: Counter Value
These bits reflect the current 4-bit counter value. The 4-bit counter value can directly be read or
written by the CPU.
The 4-bit counter increments by one for each clock generated either by the external clock edge
detector, by a Timer/Counter0 overflow, or by software using USICLK or USITC strobe bits. The
clock source depends of the setting of the USICS1..0 bits. For external clock operation a special
feature is added that allows the clock to be generated by writing to the USITC strobe bit. This
feature is enabled by write a one to the USICLK bit while setting an external clock source
(USICS1 = 1).
Note that even when no wire mode is selected (USIWM1..0 = 0) the external clock input
(USCK/SCL) are can still be used by the counter.
The Control Register includes interrupt enable control, wire mode setting, Clock Select setting,
and clock strobe.
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
USISIF
USISIE
R/W
R/W
7
0
7
0
USIOIF
USIOIE
R/W
6
0
R/W
6
0
USIPF
R/W
USIWM1
5
0
R/W
5
0
USIDC
USIWM0
R
4
0
R/W
4
0
USICNT3
R/W
3
0
USICS1
R/W
3
0
USICNT2
R/W
USICS0
2
0
R/W
2
0
USICNT1
R/W
USICLK
1
0
W
1
0
USICNT0
R/W
USITC
0
0
W
0
0
USISR
USICR
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