Clarification about Atmega128

Started by Tamilmaran S in comp.arch.embedded15 years ago 4 replies

Hi all, We are using atmega128 for one of our project. I heard that it is a 8 bit microcontroller, ok its accumulator and its data bus are...

Hi all, We are using atmega128 for one of our project. I heard that it is a 8 bit microcontroller, ok its accumulator and its data bus are 8 bit width. Then what about is address bus, is it also 8 bit width? Because for this 8 bit it can address only up to 2^8 = 256 location. Then how it can address 4096 SRAM (4K) and 131072 Flash (128K). Can anybody clear me on this doubt? Thank you ...


Clarification on Atmega128

Started by Tamilmaran S in comp.arch.embedded15 years ago 1 reply

Hi all, We are using atmega128 for one of our project. I heard that it is a 8 bit microcontroller, ok its accumulator and its data bus are...

Hi all, We are using atmega128 for one of our project. I heard that it is a 8 bit microcontroller, ok its accumulator and its data bus are 8 bit width. Then what about is address bus, is it also 8 bit width? Because for this 8 bit it can address only up to 2^8 = 256 location. Then how it can address 4096 SRAM (4K) and 131072 Flash (128K). Can anybody clear me on this doubt? Thank you ...


Advice on switching microntrollers

Started by Anonymous in comp.arch.embedded14 years ago 25 replies

Ok, flamewar time I guess. I am looking to explore new microcontrollers because the ones I have under my belt are coming up short for what I...

Ok, flamewar time I guess. I am looking to explore new microcontrollers because the ones I have under my belt are coming up short for what I need. I have a lot of experience with the 16 series of PICs from Microchip, I have played with basic Stamps (I, II, SX), some experience with Motorola's HC11, HC12 and HC16 series. Currently I use Atmel's AVR (Atmega128) at work. But in trying to b...


Using ATmega128 ADC to read One-Wire protocol

Started by rickman in comp.arch.embedded14 years ago 6 replies

I am looking at the feasibility of using a Maxim/Dallas One-Wire device on an external input that is designed to read the value of a...

I am looking at the feasibility of using a Maxim/Dallas One-Wire device on an external input that is designed to read the value of a resistor. Someone at this company thought a few resistor values would be all they needed to identify attached equipment options. Now they are out of resistors and will be needing a new way of identifying the attached equipment. I thought that the One-Wire part...


Problem w serial comms ATmega128 <-> PC

Started by A. Drosos in comp.arch.embedded14 years ago 6 replies

Problem with serial communications between ATmega128 and PC I have used WinAVR and Peter Fleury's interrupt controlled uart...

Problem with serial communications between ATmega128 and PC I have used WinAVR and Peter Fleury's interrupt controlled uart library successfully in the past with the STK500 board and the AT90S8515 and ATmega16 devices. Moving on to a bigger project I purchased the STK501 board with an ATmega128. Connecting it to the STK500 I can program the device with the default xmas_tree_leds_flashing ...


Ulf, what of these new AVRs? :)

Started by larwe in comp.arch.embedded14 years ago 75 replies

The other week I was downloading the ATmega128 datasheet to check something and I noticed the mega640/1280/1281/2560/2561. Any idea when these...

The other week I was downloading the ATmega128 datasheet to check something and I noticed the mega640/1280/1281/2560/2561. Any idea when these are going to be available? Digi-Key shows the 2560 and 2561 but zero stock; the others don't show up at all. Are the 128K flash variants going to be cheaper than the ATmega128L?


Help with TWI module on ATmega128

Started by larwe in comp.arch.embedded14 years ago 1 reply

Weird issue, but I can't receive data using the TWI module in the ATmega128. (Writing data is documented very well in the datasheet, reading...

Weird issue, but I can't receive data using the TWI module in the ATmega128. (Writing data is documented very well in the datasheet, reading data is not). The code I'm trying to use is below. It hangs while waiting for the final STOP to be sent. So it has sent SLA+R and read a byte off the device. The byte read appears to be correct, too. I know the addresses, speed etc. are OK because I ca...


Strange behavior of ATMEGA128 PORT

Started by qhhong in comp.arch.embedded14 years ago 2 replies

I have just started to study the AVR a week ago. The eight LEDs and registors are connected between the VCC and ATMEGA128 PORTB. I found that...

I have just started to study the AVR a week ago. The eight LEDs and registors are connected between the VCC and ATMEGA128 PORTB. I found that some CodeVision C programs does not work as I expected. After careful examination of the codes, I can simplify the problem to the following Assembler coding. (PORTD.0 is connected to the chattering switch) =2ECSEG _main: ; 8 PORTB=3D...


PORTD and PORTE difference in ATMEGA128?

Started by qhhong in comp.arch.embedded14 years ago 2 replies

Hello, I have connected a switch to the PD0/INT0 through 74HC14 and another switch to the PE4/INT4 through 74HC14. PD0 pin works fine. But PE4...

Hello, I have connected a switch to the PD0/INT0 through 74HC14 and another switch to the PE4/INT4 through 74HC14. PD0 pin works fine. But PE4 doesn't recognize the switch. I have checked the voltage between 74HC14 output and PE4 input. The voltage is not 5V but 1V when I push the switch. (PD0 shows normal 5V) When I disconnect the jumper line between 74HC14 and PE4 and then 74HC14 voltag...


Argh. ATmega128 users, please help?

Started by larwe in comp.arch.embedded14 years ago 41 replies

I've got to the point in a project where I am questioning all my assumptions and basically losing hair apace. My circuit is based around an...

I've got to the point in a project where I am questioning all my assumptions and basically losing hair apace. My circuit is based around an ATmega128, running at 16MHz off an ext xtal. The prototype board worked 100% fine after I tied VREF to +5V; apparently the JTAG interface isn't happy unless VREF is present. My "final" board - with no substantial change from the old circuit - is behaving ...


State of I/O pins during brownout on Atmega128

Started by Anonymous in comp.arch.embedded14 years ago 5 replies

Hi, I am working with an AVR Atmega128. Is it possible that during a brownout, I/O pins designated as Output could potentially float? Or...

Hi, I am working with an AVR Atmega128. Is it possible that during a brownout, I/O pins designated as Output could potentially float? Or if they are inputs with pullups? Basically I am wondering if the chip enters an undefined state at any point during a brownout. Any help would be greatly appreciated. Thanks in advance. --Dima


ENC28j60 or CS8900A

Started by rf_xport in comp.arch.embedded14 years ago 3 replies

Hi, I have a microcontroller (ATMega128) and I want to connect it to internet. At first I need a ethernet controller(MAC & PHY ethernet). I...

Hi, I have a microcontroller (ATMega128) and I want to connect it to internet. At first I need a ethernet controller(MAC & PHY ethernet). I have known some ICs: ENC28j60, CS8900 (3v), RTL8019A... I think CS8900A and ENC28j60 are better for my project. but I don't know which of them is better ? Is there anybody who has experience with them? As I am in hurry, I will be so thankful if y...


connect ATMega128 to internet

Started by rf_xport in comp.arch.embedded14 years ago 6 replies

I want to connect a ATMega128 to internet. I am looking for a low cost and easy solution. Is it possible to help me. As I am on time...

I want to connect a ATMega128 to internet. I am looking for a low cost and easy solution. Is it possible to help me. As I am on time constraint, I will be so thankful if anybody reply me as soon as possible. -thanks.


atmega128 date/time management

Started by Didrik Pinte in comp.arch.embedded14 years ago 9 replies

Hi, I'm a newbie into embedded programming. The project i'm working on is based on an Atmel avr atmega128 device (with a GSM device connected...

Hi, I'm a newbie into embedded programming. The project i'm working on is based on an Atmel avr atmega128 device (with a GSM device connected to it). The environment used is IAR EW with AVRStudio. Using the time.h library, i try to get the actual time with the following code : --------------------------------------------------- time_t now; time(&now); printf("Time is %s\r\n", ctime(...


Atmega128 or MSP430 for low power, decent performance?

Started by rektide in comp.arch.embedded13 years ago 7 replies

I've been planning on using a MSP430 for all my very low powered control work for a while, and was about to order the dev kit ($99, cant argue...

I've been planning on using a MSP430 for all my very low powered control work for a while, and was about to order the dev kit ($99, cant argue with taht). Eventually I'd like to get TinyOS running, hopefully to simplify some of my own work, and I noticed that 2 of the 3 reference platforms are ATmega128 platforms. I'm pretty sure the MSP430 cant be beat for power consumption, but i really...


i2c coding problem

Started by tanu in comp.arch.embedded13 years ago 1 reply

Hi all I am using ATmega128 controller and using i2c bus eeprom to increase its memory space . I have i2c header file in my codevision avr and...

Hi all I am using ATmega128 controller and using i2c bus eeprom to increase its memory space . I have i2c header file in my codevision avr and i used them and change that accordingly but when i m reading my eeprom i m geting nothing i think that my code is either not able to generate the clock pulse or not able to write the data into eeprom i m not getting ,how to genrate the clk ? #in...


AT24C512 partial write allowed

Started by tanu in comp.arch.embedded13 years ago

Hi, Need your help I am using atmega128 microcontoller interfacing it with at24c512(i2c bus). The code is running and i am getting data...

Hi, Need your help I am using atmega128 microcontoller interfacing it with at24c512(i2c bus). The code is running and i am getting data . butt i am not able to write/read more then 2 pages(128 bytes per page) at a time. i amnot getting where i m going wrong. // 2 Wire Bus initialization // Generate Acknowledge Pulse: On // 2 Wire Bus Slave Address: 00h // General Call Recognition: ...


Serial communication of ATMega128

Started by sindhu in comp.arch.embedded13 years ago 4 replies

Hi all, Iam working on Atmega128 and STK500.Iam new to this. I need to transmit a character from controller.I have given the...

Hi all, Iam working on Atmega128 and STK500.Iam new to this. I need to transmit a character from controller.I have given the code below. #include"iom128v.h" #include "io.h" unsigned char data; unsigned int baud; unsigned int i; int transmit(unsigned char); void USART0_Init( unsigned int baud) { UBRR0H=0x96; UBRR0L=0x00; UCSR0B=0x08; UCSR0C=0x06; } int transmit(unsigned ...


CRC calculation

Started by janka vietzen in comp.arch.embedded13 years ago

I dont have many modbus manuals but there are 2 diffrent code samples for crc written in C. One uses 2 bested byte - bit loops and the other uses...

I dont have many modbus manuals but there are 2 diffrent code samples for crc written in C. One uses 2 bested byte - bit loops and the other uses 255 byte lookup tables for low and highbyte each. Unfortunately I dont tried any Compilers for Atmels ATmega128 (probably there is a gcc available) and even the cpu family is new for me why i decided to start with assembler


"Executing code in SRAM" with AVR

Started by jamie in comp.arch.embedded13 years ago 9 replies

Hello I have a question about "executing code in SRAM" with Atmega128 MCU. I know instructions (code) in flash rom area can be executed by...

Hello I have a question about "executing code in SRAM" with Atmega128 MCU. I know instructions (code) in flash rom area can be executed by AVR cpu and now I'm wondering if the code in SRAM can also be executed. Imagine I have some AVR instructions ( or function code ) in SRAM area, If I jump program counter to the area ( in SRAM ) then will the instruction be executed without any proble...