ATUC128L4U Atmel Corporation, ATUC128L4U Datasheet - Page 567

• Manufacturer Part Number: ATUC128L4U
• Manufacturer: Atmel Corporation

Specifications of ATUC128L4U

• Flash (kbytes): 128 Kbytes
• Pin Count: 48
• Max. Operating Frequency: 50 MHz
• Cpu: 32-bit AVR
• # Of Touch Channels: 17
• Hardware Qtouch Acquisition: Yes
• Max I/o Pins: 36
• Ext Interrupts: 36
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 1
• Twi (i2c): 2
• Uart: 4
• Lin: 4
• Ssc: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 12
• Adc Speed (ksps): 460
• Analog Comparators: 8
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 16
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.62 to 3.6
• Operating Voltage (vcc): 1.62 to 3.6
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 6
• Output Compare Channels: 18
• Input Capture Channels: 12
• Pwm Channels: 35
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

23.8.2.4
23.8.2.5
23.8.3
32142A–12/2011
Slave Transmitter Mode
Clock Stretching
Bus Errors
In I²C mode:
In SMBus mode:
Any slave or bus master taking part in a transfer may extend the TWCK low period at any time.
The TWIS may extend the TWCK low period after each byte transfer if CR.STREN is one and:
If CR.STREN is zero and:
If a bus error (misplaced START or STOP) condition is detected, the SR.BUSERR bit is set and
the TWIS waits for a new START condition.
If the TWIS matches an address in which the R/W bit in the TWI address phase transfer is set, it
will enter slave transmitter mode and set the SR.TRA bit (note that SR.TRA is set one
CLK_TWIS cycle after the relevant address match bit in the same register is set).
After the address phase, the following actions are performed:
• The address in CR.ADR is checked for address match if CR.SMATCH is one.
• The General Call address is checked for address match if CR.GCMATCH is one.
• The address in CR.ADR is checked for address match if CR.SMATCH is one.
• The Alert Response Address is checked for address match if CR.SMAL is one.
• The Default Address is checked for address match if CR.SMDA is one.
• The Host Header Address is checked for address match if CR.SMHH is one.
• Module is in slave transmitter mode, data should be transmitted, but THR is empty, or
• Module is in slave receiver mode, a byte has been received and placed into the internal
• Stretch-on-address-match bit CR.SOAM=1 and slave was addressed. Bus clock remains
• Module is in slave transmitter mode, data should be transmitted but THR is empty: Transmit
• Module is in slave receiver mode, a byte has been received and placed into the internal
1. If SMBus mode and PEC is used, NBYTES must be set up with the number of bytes to
2. Byte to transmit depends on I²C/SMBus mode and CR.PEC:
3. The data byte in the shifter is transmitted.
shifter, but the Receive Holding Register (RHR) is full, or
stretched until all address match bits in the Status Register (SR) have been cleared.
the value present in THR (the last transmitted byte or reset value), and set SR.URUN.
shifter, but RHR is full: Discard the received byte and set SR.ORUN.
transmit. This is necessary in order to know when to transmit the PEC byte. NBYTES
can also be used to count the number of bytes received if using DMA.
– If in I²C mode or CR.PEC is zero or NBYTES is non-zero: The TWIS waits until THR
– SMBus mode and CR.PEC is one: If NBYTES is zero, the generated PEC byte is
contains a valid data byte, possibly stretching the low period of TWCK. After THR
contains a valid data byte, the data byte is transferred to a shifter, and then
SR.TXRDY is changed to one because the THR is empty again.
automatically transmitted instead of a data byte from THR. TWCK will not be
stretched by the TWIS.
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