ATmega16U2 Atmel Corporation, ATmega16U2 Datasheet - Page 252

• Manufacturer Part Number: ATmega16U2
• Manufacturer: Atmel Corporation

Specifications of ATmega16U2

• Flash (kbytes): 16 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 22
• Ext Interrupts: 21
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• 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: 5
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

25.7
25.7.1
25.7.2
25.7.3
7799D–AVR–11/10
Parallel Programming
Enter Programming Mode
Considerations for Efficient Programming
Chip Erase
Table 25-13. Command Byte Bit Encoding
The following algorithm puts the device in parallel programming mode:
The loaded command and address are retained in the device during programming. For efficient
programming, the following should be considered.
The Chip Erase will erase the Flash and EEPROM
not reset until the program memory has been completely erased. The Fuse bits are not
changed. A Chip Erase must be performed before the Flash and/or EEPROM are
reprogrammed.
Note:
Load Command “Chip Erase”
1. Apply 4.5 - 5.5V between V
2. Set RESET to “0” and toggle XTAL1 at least six times.
3. Set the Prog_enable pins listed in
4. Apply 11.5 - 12.5V to RESET. Any activity on Prog_enable pins within 100 ns after
5. Wait at least 50 µs before sending a new command.
• The command needs only be loaded once when writing or reading multiple memory
• Skip writing the data value 0xFF, that is the contents of the entire EEPROM (unless the
• Address high byte needs only be loaded before programming or reading a new 256 word
1. Set XA1, XA0 to “10”. This enables command loading.
2. Set BS1 to “0”.
3. Set DATA to “1000 0000”. This is the command for Chip Erase.
4. Give XTAL1 a positive pulse. This loads the command.
5. Give WR a negative pulse. This starts the Chip Erase. RDY/BSY goes low.
locations.
EESAVE Fuse is programmed) and Flash after a Chip Erase.
window in Flash or 256 byte EEPROM. This consideration also applies to Signature bytes
reading.
100 ns.
+12V has been applied to RESET, will cause the device to fail entering programming
mode.
Command Byte
1. The EEPRPOM memory is preserved during Chip Erase if the EESAVE Fuse is programmed.
0001 0001
0000 1000
0000 0100
0000 0010
0000 0011
Command Executed
Write EEPROM
Read Signature Bytes and Calibration byte
Read Fuse and Lock bits
Read Flash
Read EEPROM
CC
and GND.
Table 25-11 on page 251
(1)
ATmega8U2/16U2/32U2
memories plus Lock bits. The Lock bits are
to “0000” and wait at least
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