ATmega16U2 Atmel Corporation, ATmega16U2 Datasheet - Page 24

• 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

7.5.4
7.5.5
7799D–AVR–11/10
GPIOR2 – General Purpose I/O Register 2
GPIOR1 – General Purpose I/O Register 1
The next code examples show assembly and C functions for reading the EEPROM. The exam-
ples assume that interrupts are controlled so that no interrupts will occur during execution of
these functions.
Note:
Bit
0x2B (0x4B)
Read/Write
Initial Value
Bit
0x2A (0x4A)
Read/Write
Initial Value
Assembly Code Example
C Code Example
EEPROM_read:
unsigned char EEPROM_read(unsigned int uiAddress)
{
}
; Wait for completion of previous write
sbic EECR,EEPE
rjmp EEPROM_read
; Set up address (r18:r17) in address register
out EEARH, r18
out EEARL, r17
; Start eeprom read by writing EERE
sbi EECR,EERE
; Read data from Data Register
in
ret
/* Wait for completion of previous write */
while(EECR & (1<<EEPE))
/* Set up address register */
EEAR = uiAddress;
/* Start eeprom read by writing EERE */
EECR |= (1<<EERE);
/* Return data from Data Register */
return EEDR;
1. See “Code Examples” on page 6.
;
r16,EEDR
MSB
MSB
R/W
R/W
7
0
7
0
(1)
R/W
R/W
6
0
6
0
(1)
R/W
R/W
5
0
5
0
R/W
R/W
4
0
4
0
ATmega8U2/16U2/32U2
R/W
R/W
3
0
3
0
R/W
R/W
2
0
2
0
R/W
R/W
1
0
1
0
LSB
R/W
LSB
R/W
0
0
0
0
GPIOR2
GPIOR1
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