ATMEGA48PA-MNR Atmel, ATMEGA48PA-MNR Datasheet - Page 273

• Manufacturer Part Number: ATMEGA48PA-MNR
• Description: MCU AVR 4KB FLASH 20MHZ 28QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA48PA-MNR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: SPI, UART, I2C
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 23
• Operating Supply Voltage: 1.8 V to 5.5 V
• Maximum Operating Temperature: + 105 C
• Mounting Style: SMD/SMT
• Operating Temperature Range: - 40 C to + 85 C
• Processor To Be Evaluated: ATMEGA48A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

25.2.5
8161D–AVR–10/09
Simple Assembly Code Example for a Boot Loader
Note that the RWWSB bit will always be read as zero in ATmega48PA. Nevertheless, it is rec-
ommended to check this bit as shown in the code example, to ensure compatibility with devices
supporting Read-While-Write.
.equ PAGESIZEB = PAGESIZE*2
.org SMALLBOOTSTART
Write_page:
Wrloop:
;-the routine writes one page of data from RAM to Flash
; the first data location in RAM is pointed to by the Y pointer
; the first data location in Flash is pointed to by the Z-pointer
;-error handling is not included
;-the routine must be placed inside the Boot space
; (at least the Do_spm sub routine). Only code inside NRWW section can
; be read during Self-Programming (Page Erase and Page Write).
;-registers used: r0, r1, temp1 (r16), temp2 (r17), looplo (r24),
; loophi (r25), spmcrval (r20)
; storing and restoring of registers is not included in the routine
; register usage can be optimized at the expense of code size
;-It is assumed that either the interrupt table is moved to the Boot
; loader section or that the interrupts are disabled.
; Page Erase
ldi
rcallDo_spm
; re-enable the RWW section
ldi
rcallDo_spm
; transfer data from RAM to Flash page buffer
ldi
ldi
ld
ld
ldi
rcallDo_spm
adiw ZH:ZL, 2
sbiw loophi:looplo, 2
brne Wrloop
; execute Page Write
subi ZL, low(PAGESIZEB)
sbci ZH, high(PAGESIZEB)
ldi
rcallDo_spm
; re-enable the RWW section
ldi
rcallDo_spm
; read back and check, optional
ldi
ldi
subi YL, low(PAGESIZEB)
spmcrval, (1<<PGERS) | (1<<SELFPRGEN)
spmcrval, (1<<RWWSRE) | (1<<SELFPRGEN)
looplo, low(PAGESIZEB)
loophi, high(PAGESIZEB)
r0, Y+
r1, Y+
spmcrval, (1<<SELFPRGEN)
spmcrval, (1<<PGWRT) | (1<<SELFPRGEN)
spmcrval, (1<<RWWSRE) | (1<<SELFPRGEN)
looplo, low(PAGESIZEB)
loophi, high(PAGESIZEB)
ATmega48PA/88PA/168PA/328P
;PAGESIZEB is page size in BYTES, not words
;init loop variable
;not required for PAGESIZEB<=256
;use subi for PAGESIZEB<=256
;restore pointer
;not required for PAGESIZEB<=256
;init loop variable
;not required for PAGESIZEB<=256
;restore pointer
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