U731219879 rc: Created page with "Learning '''inline assembly language''' on the Arduino AVR 8-bit platform is a daunting task The ATmel '''AVR Assembly Language''' 8-bit Instruction Set
http://www.atmel..."

2019-03-23T03:49:25Z

Created page with "Learning '''inline assembly language''' on the Arduino AVR 8-bit platform is a daunting task The ATmel '''AVR Assembly Language''' 8-bit Instruction Set http://www.atmel..."

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Learning '''inline assembly language''' on the Arduino AVR 8-bit platform is a daunting task

The ATmel '''AVR Assembly Language''' 8-bit Instruction Set 
http://www.atmel.com/images/atmel-0856-avr-instruction-set-manual.pdf

* Connect '''USBtiny''' to '''ATmega328P Target Board'''. 
* Test the connection to programmer: '''''avrdude -p m328p -c usbtiny -v''''' 
* Connect LED with pull down resistor to '''Pin D13''' on '''ATmega328P Target bd'''. (Not needed if using Target Bd built in Yellow LED) 
* Open '''Arduino IDE''' and change the following settings: Under the '''Tools''' tab 

'''Board:''' ='''"Arduino/Genunio Uno"'''
'''Programmer:''' = '''"USBtiny or USBasp"'''
* Copy-Paste/Load '''ASM-blink.ino''' Arduino file. ('''Do not Flash until instructed ''') 

// ASM-blink.ino MicroRusty 2018
// Blink Program using assembly language in the Ardion IDE
// AVR RISC processors offers to embed assembly language code into C programs
void setup() {
asm("sbi 0x04, 5"); //sbi= Set bit in I/O Data Direction Register DDRB 0x4 with the value 5
}
void loop() {
asm("start:");
asm("sbi 0x05, 5"); // sbi= Set bit in I/O Register-PortB bit 0x5 with the value 5 (00010000)
asm("ldi r16,40 \n\t rcall delay"); // Load imediate Reqister r16 with vaulue 40 - RCALL Relative Subroutine Call
asm("cbi 0x05, 5"); // cbi= Clear bit in I/O Register-PortB bit 0x5 with the value 5 (00000000)
asm("ldi r16,40 \n\t rcall delay"); // Load imediate Reqister r16 with vaulue 40 - RCALL Relative Subroutine Call
asm("rjmp start"); // Relative Jump back to start 
asm("delay:"); // Delay subroutine called by RCALL
asm("dec r8"); // Decrease r8 by 1 starting at 255
asm("brne delay"); // keep going until 0
asm("dec r9"); // Decrease r9 by 1 starting at 255
asm("brne delay"); // keep going until 0
asm("dec r16"); // Decrease r16 by 1 starting at 40
asm("brne delay"); // Keep going until 0
asm("ret"); // Return from subroutine after Three nested delay loops -ugh
}

* Generate the binary file by selecting under the '''Sketch''' Tab: '''''"Export complied Binary"'''''
* Flash the chip by Selecting '''Upload Using Programmer''' under '''Sketch''' Tab in '''Arduino IDE'''. 

Sketch uses '''474 bytes (1%)''' of program storage space. Maximum is 32256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes

* Notice the speed of the blinking LED at 1MHz. Try the different clock speeds 
'''1 MHz'''
avrdude -p m328p -c usbtiny -v -U lfuse:w:0x62:m -U hfuse:w:0xD9:m -U efuse:w:0xFF:m
'''8 MHz'''
avrdude -p m328p -c usbtiny -v -U lfuse:w:0xE2:m -U hfuse:w:0xD6:m -U efuse:w:0xFF:m
'''16 MHz'''
avrdude -p m328p -c usbtiny -v -U lfuse:w:0xFF:m -U hfuse:w:0xDE:m -U efuse:w:0xFF:m

'''AVRASM2''' is the ASM compiler and was once a stand alone program that has now since been incorporated into '''ATMEL Studio''' 
I will not cover AVRASM2 in this workshop. AVRASM2 will be covered in part of ATMEL Studio Workshop that will be sometime in the furture. 

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==[[ AVRDUDE Class]]==

Programming AVR Assembly language - Revision history

U731219879 rc: Created page with "Learning '''inline assembly language''' on the Arduino AVR 8-bit platform is a daunting task The ATmel '''AVR Assembly Language''' 8-bit Instruction Set http://www.atmel..."

U731219879 rc: Created page with "Learning '''inline assembly language''' on the Arduino AVR 8-bit platform is a daunting task The ATmel '''AVR Assembly Language''' 8-bit Instruction Set
http://www.atmel..."