Bootloader Differences

-

hi all,

i trying understand bootloaders, contains , how go writing one.

can clear of doubts have when started exploring same?

1. why there 2 folders named arduino-usbdfu , arduino-usbserial in arduino firmwares folder? different in 2 versions?

2. in arduino uno or mega, understanding, onboard atmega16u2 chip usb serial conversion between pc , atmega328 or atmega2560 chip. or else too?

if that, why there again 2 different bootloading files of atmega16u2 of mega , uno(arduino-usbserial-mega.hex , arduino-usbserial-uno.hex in arduino-usbserial folder)? why chip dependent?

3. there tutorial or writeup somewhere on how go writing arduino bootloader(for new chip) because know process?

thanking guys in advance :)

quote
3. there tutorial or writeup somewhere on how go writing arduino bootloader(for new chip) because know process?
look @ datasheet part want use.  atmel has sample code bootloader in datasheets have seen.
for example, in 328p:
code: [select]

27.8.13 simple assembly code example boot loader
;-the routine writes 1 page of data ram flash
; first data location in ram pointed y pointer
; first data location in flash pointed z-pointer
;-error handling not included
;-the routine must placed inside boot space
; (at least do_spm sub routine). code inside nrww section can
; read during self-programming (page erase , page write).
;-registers used: r0, r1, temp1 (r16), temp2 (r17), looplo (r24),
; loophi (r25), spmcrval (r20)
; storing , restoring of registers not included in routine
; register usage can optimized @ expense of code size
;-it assumed either interrupt table moved boot
; loader section or interrupts disabled.
.equ pagesizeb = pagesize*2 ;pagesizeb page size in bytes, not words
.org smallbootstart
write_page:
; page erase
ldi spmcrval, (1<<pgers) | (1<<spmen)
call do_spm
; re-enable rww section
ldi spmcrval, (1<<rwwsre) | (1<<spmen)
call do_spm
; transfer data ram flash page buffer
ldi looplo, low(pagesizeb) ;init loop variable
ldi loophi, high(pagesizeb) ;not required pagesizeb<=256
wrloop:
ld r0, y+
ld r1, y+
ldi spmcrval, (1<<spmen)
call do_spm
adiw zh:zl, 2
sbiw loophi:looplo, 2 ;use subi pagesizeb<=256
brne wrloop
; execute page write
subi zl, low(pagesizeb) ;restore pointer
sbci zh, high(pagesizeb) ;not required pagesizeb<=256
ldi spmcrval, (1<<pgwrt) | (1<<spmen)
call do_spm
; re-enable rww section
ldi spmcrval, (1<<rwwsre) | (1<<spmen)
call do_spm
; read , check, optional
ldi looplo, low(pagesizeb) ;init loop variable
ldi loophi, high(pagesizeb) ;not required pagesizeb<=256
subi yl, low(pagesizeb) ;restore pointer
sbci yh, high(pagesizeb)
rdloop:
lpm r0, z+
ld r1, y+
cpse r0, r1
jmp error
sbiw loophi:looplo, 1 ;use subi pagesizeb<=256
brne rdloop
; return rww section
; verify rww section safe read
return:
in temp1, spmcsr
sbrs temp1, rwwsb ; if rwwsb set, rww section not ready yet
ret
; re-enable rww section
ldi spmcrval, (1<<rwwsre) | (1<<spmen)
call do_spm
rjmp return
do_spm:
; check previous spm complete
wait_spm:
in temp1, spmcsr
sbrc temp1, spmen
rjmp wait_spm
; input: spmcrval determines spm action
; disable interrupts if enabled, store status
in temp2, sreg
cli
; check no eeprom write access present
wait_ee:
sbic eecr, eepe
rjmp wait_ee
; spm timed sequence
out spmcsr, spmcrval
spm
; restore sreg (to enable interrupts if enabled)
out sreg, temp2
ret
you need isp programmer access memory via spi pins install bootloader, , set fuses clock type using, brownout levels, etc. if want use besides factory programming.


Arduino Forum > Using Arduino > Microcontrollers > Bootloader Differences


arduino

Comments

Post a Comment

Popular posts from this blog

invalid use of void expresion in FlexiTimer2 library

-
Image
hello, first post asking in forum patient if dont correctly   well, im trying make robot evades obstacles , uses interrupts in order distances. ive used flexitimer2 run void function each 5ms, problem whe try verify program says me there error in use of flexitimer.    code: [select] flexitimer2::set(1, 1.0/1000, rastreodistanciamin()); i copy code below, please can tell error , how solve it, ive been loking dont know do. thank you code: [select] #include <flexitimer2.h> #include <servo.h> //motor a int ena = 7; int in1=6; int in2 = 5; //motor b int in3=11; int in4=10; int enb=9; servo cabeza; //hc-sr04 device int echo = 13; int triger = 12; //it use hc-sr04 determine , return distance in front of him int calculodistancia(){   volatile int tiempo;   volatile int distancia;   digitalwrite(triger,low); /* por cuestión de estabilización del sensor*/   delaymicroseconds(5);   digitalwrite(triger, high); /* envío del pulso ultrasónico*/   delaymicroseconds(10);   tiem
Read more

error: a function-definition is not allowed here before '{' token

-
i'm new member. me pls code: [select] void manhinh1(){                              tempc = analogread(adc);   tempc = tempc * 0.48828125;                                          lcd.setcursor(0, 0); lcd.print("nhiet: ");                                      lcd.setcursor(7, 0); lcd.print(tempc);   lcd.setcursor(13,0); lcd.print((char)223);    lcd.setcursor(14,0); lcd.print("c");   if(max > min){     if (tempc > max)            {digitalwrite(fan, low);           lcd.setcursor(2, 1); lcd.print("lam mat.....");}     else if (tempc < min)           {digitalwrite(hot, low);           lcd.setcursor(2, 1); lcd.print("dang suoi...");           delay(10000); }     else if (tempc > min && tempc < max)           {digitalwrite(fan, high);            digitalwrite(hot, high);            lcd.setcursor(2, 1); lcd.print("on dinh!!");}              }    else if (max < min){    lcd.setcursor(0, 1);               
Read more

LED Strip Code

-
i downloaded code. here have several single leds flashing music microphone. in project, instead of single rgb leds, have 5 rgb led strips. need change in code? led strip 10m supernight rgb strip cut 5 equal strips. // arduino pin numbers const int do_pin = 2; const int ao_pin = 0; int sound; int led1 = 8; int led2 = 9; int led3 = 10; int led4 = 11; int led5 = 12;   void setup() {   pinmode(do_pin, input);   pinmode(led1, output);   pinmode(led2, output);   pinmode(led3, output);   pinmode(led4, output);   pinmode(led5, output);   serial.begin(9600); }   void loop() {     if (sound > 31) {     digitalwrite(led1, high);   }     if (sound < 31) {     digitalwrite(led1, low);   }     if (sound > 35) {     digitalwrite(led2, high);   }     if (sound < 35) {     digitalwrite(led2, low);   }     if (sound > 40) {     digitalwrite(led3, high);   }     if (sound < 40) {     digitalwrite(led3, low);   }     if (sound > 45) {     digitalwrite(led4, high);   }     if
Read more