ATmega32 40pin Minimum Development Board

Minimum DevBoard

The Arduino Uno is a minimum development board. It has an integrated circuit chip in a socket. You may order these parts separately or in kits.

Do not handle chips more than you have to. Use anti-static protection, the shiny material is a component bag.

Check pin numbers and connections. Alignment notches, triangle and dot symbols help orientation. Use the ZIF zero insertion force lever to pinch the chip tightly into the socket.

We call these chips DIP dual inline pin because of the shape. The same processors are available in compact surface-mount packages.

ATmega32 vs ATmega328p

Almost the same chip. ATmega32 has a PORTA that the Uno does not have. If your Arduino project needs more IO then maybe this is the chip for you. Same RAM for your program to run, same flash.

Compare the two. Equipped with ATmega328p the 28pin board is equivalent to the Uno. The ATmega32 has more IO pins so let's connect an LED bar to PORTA.

This ATmega32 minimum development board has an LED connected to PA0 the first pin of PORTA. The second LED is a red power indicator.

ATmega8 chips have half the RAM of an ATmega328p and a quarter of the flash. But they fit the same pinout footprint. The p in 328p is for a low power feature.

Code

Here is assembler code to binary count on PORTA. The include file m32def.inc maps out the board for the compiler and tells it how to deal with reserved key words such as DDRA and PORTA.

.include "m32def.inc"
    .def	mask 	= r16	; mask register
    .def	ledR 	= r17	; led register
    .def	oLoopR 	= r18	; outer loop register
    .def	iLoopRl = r24	; inner loop register low
    .def	iLoopRh = r25	; inner loop register high
    .equ	oVal 	= 80	; outer loop value
    .equ	iVal 	= 800	; inner loop value
    .cseg
    .org	0x00
    clr	    ledR		; clear led register to zero
    ldi	    mask,0xFF		; load the mask register 11111111
    out	    DDRA,mask		; set PORTA to all 8 bits OUT
start:
    out	    PORTA,ledR		; write led register to PORTA
    inc     ledR		; increment ledR from 0 to 255
    ldi     oLoopR,oVal		; initialize outer loop count
oLoop:
     ldi    iLoopRl,LOW(iVal)	; intialize inner loop count in inner
     ldi    iLoopRh,HIGH(iVal)	; loop high and low registers
iLoop:
    sbiw    iLoopRl,1	        ; decrement inner loop register
    brne    iLoop		; branch to iLoop if iLoop register != 0
    dec	    oLoopR		; decrement outer loop register
    brne    oLoop		; branch to oLoop if outer loop register != 0
    rjmp    start		; jump back to start

This same code will not compile for a Uno board or most other Atmel processors. ATmega32 have a PORTA circuit and ATmega328 do not.

MPLab X IDE

In MPLabX C Language Program Arduino Uno we setup the MPLabX IDE. MicroChip Studio is needed for this project, as well.

Open MPLab X. Menu File->New Project or Ctrl+Shift+N from keyboard. MicroChip Embedded Standalone Project click Next.

Type ATmega32 into Device: there are many slightly different processors.

MPLab will scan the computer and find compilers that can work with the ATmega32. Choose assembler avrasm2 (installed with MicroChip Studio).

Name the project at32 and Finish. Pay attention the Project Folder location. We will have to manually upload the hex file we are going to generate.

New AssemblyFile.asm

Our new project has no source code. Right click on the Source Files folder and New->AssemblyFile.asm...

Accept the default name. We are creating an assembly language program file named newAsmTemplate.asm. It is an attachment to the project, you may have to rename the file.

Paste in our code from above. Our program toggles IO pins on PORTA with a binary count. Change oVal and iVal to change the speed of the count.

Build Main Project

Build the project (generate hex file) click menu Production->Build Main Project or press F11 on the keyboard.

Build SUCCESSFUL now find the hex file.

Firmware Hex File

Locate the folder where MPLab has deposited the hex file. We can copy this file, rename it, move it to other folders.

Open in Terminal

Open a terminal command window in that directory (try right click in the folder window and open terminal).

The prompt shows the directory path. Type in dir for a directory listing.

Connect PC to DevBoard

This project uses USBasp or USBtiny programmer devices. They can provide enough power for a basic board. Arduino IDE and MicroChip Studio can upload directly but we will use the command terminal window.

Avrdude

When you install MicroChip Studio to get the avrasm2 program you also install avrdude. It is the program that uploads Arduino sketches. Open the terminal command window on your PC and go to the directory that contains our hex file.

Type in

avrdude -p m32 -c usbasp -U flash:w:at32.X.production.hex:i

Progress bars will cross the computer screen, LEDs may blink on the programmer.

The ATmega32 MCU should be doing a binary count on PORTA.

Bootloader?

I don't think so. This chip came from the factory with no bootloader. We can continue to program with ICSP in circuit system programmer devices like the USBasp or USBtiny dongles.