ATmega8U2 Atmel Corporation, ATmega8U2 Datasheet - Page 22

• Manufacturer Part Number: ATmega8U2
• Manufacturer: Atmel Corporation

Specifications of ATmega8U2

• Flash (kbytes): 8 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 22
• Ext Interrupts: 20
• 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

22
;**************************************************************************
**
flash_prg_page:
;*F************************************************************************
**
; NAME: flash_page_erase
;--------------------------------------------------------------------------
--
; PARAMS:
;--------------------------------------------------------------------------
--
; PURPOSE:
;--------------------------------------------------------------------------
--
; NOTE:
not
; erase the hardware temporary temp buffer.
; This function is for bootloader usage
;--------------------------------------------------------------------------
--
; REQUIREMENTS:
;**************************************************************************
**
flash_page_erase:
RCALL
MOV
MOV
OUT
LDI
OUT SPMCSR,R20; argument 2 decides function (r18)
SPM
RCALL
RCALL
RET
RCALL
MOV
MOV
OUT
LDI
OUT SPMCSR, R20; argument 2 decides function (r18)
SPM
RCALL
;RCALL
;
RET
This function does nt set the RWWSE bit after erase. Thus it does
WAIT_SPMEN
R31,R17
R30,R16
RAMPZ, R18
R20,$05
flash_rww_enable
WAIT_SPMEN
R31,R17
R30,R16
RAMPZ, R18
R20,$03
WAIT_SPMEN
WAIT_SPMEN
flash_rww_enable CAUTION DO NOT ACTIVATE HERE or
you will loose the entire page buffer content !!!
R18:17:R16: The byte address of the page
Launch the erase sequence of the target page
;Store program memory
;Store program memory
;Wait for SPMEN flag cleared
;move adress to z pointer (R31=ZH R30=ZL)
;(1<<PGWRT) + (1<<SPMEN))
;Wait for SPMEN flag cleared
;move adress to z pointer (R31=ZH R30=ZL)
;(1<<PGERS) + (1<<SPMEN)))
;Wait for SPMEN flag cleared
;Wait for SPMEN flag cleared
7618C–AVR–07/08