ATtiny20 Atmel Corporation, ATtiny20 Datasheet - Page 157

• Manufacturer Part Number: ATtiny20
• Manufacturer: Atmel Corporation

Specifications of ATtiny20

• Flash (kbytes): 2 Kbytes
• Pin Count: 14
• Max. Operating Frequency: 12 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 5
• Hardware Qtouch Acquisition: Yes
• Max I/o Pins: 12
• Ext Interrupts: 12
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.12
• 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: 3
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

18.4.1
18.4.2
18.5
8235B–AVR–04/11
Instruction Set
Message format
Exception Handling and Synchronisation
The access layer can also access the data space, either directly or indirectly using the Pointer
Register (PR) as the address pointer. The data space is accessible using the SLD, SST, SIN
and SOUT instructions. The address pointer can be stored in the Pointer Register using the
SLDPR instruction.
Each message comprises an instruction followed by one or more byte operands. The instruction
is always sent by the external programmer. Depending on the instruction all the following oper-
ands are sent either by the external programmer or by the TPI.
The messages can be categorized in two types based on the instruction, as follows:
All the instructions except the SKEY instruction require the instruction to be followed by one byte
operand. The SKEY instruction requires 8 byte operands. For more information, see the TPI
instruction set on
Several situations are considered exceptions from normal operation of the TPI. When the TPI
physical layer is in receive mode, these exceptions are:
When the TPI physical layer is in transmit mode, the possible exceptions are:
All these exceptions are signalized to the TPI access layer. The access layer responds to an
exception by aborting any on-going operation and enters the error state. The access layer will
stay in the error state until a BREAK character has been received, after which it is taken back to
its default state. As a consequence, the external programmer can always synchronize the proto-
col by simply transmitting two successive BREAK characters.
The TPI has a compact instruction set that is used to access the TPI Control and Status Space
(CSS) and the data space. The instructions allow the external programmer to access the TPI,
the NVM Controller and the NVM memories. All instructions except SKEY require one byte oper-
and following the instruction. The SKEY instruction is followed by 8 data bytes. All instructions
are byte-sized.
• Write messages. A write message is a request to write data. The write message is sent
• Read messages. A read message is a request to read data. The TPI reacts to the request by
• The TPI physical layer detects a parity error.
• The TPI physical layer detects a frame error.
• The TPI physical layer recognizes a BREAK character.
• The TPI physical layer detects a data collision.
entirely by the external programmer. This message type is used with the SSTCS, SST,
STPR, SOUT and SKEY instructions.
sending the byte operands. This message type is used with the SLDCS, SLD and SIN
instructions.
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