Programmers For AVR Serial & Parallel
Programming Hardware for AVR’s
As hobbyist we always search for some good & cost effective programmer hardware for our specific microcontroller. Here i am trying to describe how to make some serial & parallel port based programmer that supports standered development tools like WinAVR, PonyProg etc.
- Simple serial programmer (PonyProg compatible)
- Serial Programmer (WinAVR compatible)
- Parallel Port BSD Prog
Parallel Port Programmer
First let us discuss Parallel Port BSD Programmer. Originally from http://www.bsdhome.com/avrdude/. This programmer is very easy to make and as easy to use. This is a SPI based programmer, Serial peripheral Interface facility present in AVR series is very useful for programming the controller. Pins used on AVR is MOSI, MISO, SCK, RESET. Few resisters and thats it. Be careful with resisters do not skip any of them. Here is the circuit diagram.
Parallel Port PinOut
This programmer is compatible to WinAVR. In Makefile mention programmer as “bsd” and port as lpt1.
Note- To use this programmer in WinAVR you have to install drivers because Windows XP do not allow direct access to LPT port. Goto WinAVR install directory in your Windows Drive (Usually C:/), goto bin directory there you will find a batch file named as install_giveio.bat run that file. This will install LPT driver. Now you are done to use this bsd programmer with WinAVR.
Serial PORT Programmer Compatible to PONYPROG
Pony Prog Interface Setup for Programmer
Another Serial Port Programmer (PonySer)
PonyProg Interface setup for This Programmer
NOTE
This programmer is directly compatible to both PonyProg as well as WinAVR. In WinAVR you can use this programmer by specifying programmer as “ponyser” while cofiguring MAKEFILE.
devesh@electroons.com
Accessing internal EEPROM AVR
How to access Internal EEPROM in AVR ATmega8/16/32
Almost all of the controllers in MegaAVR Family has internal EEPROM, which is as we know a kind of Non-Volatile Memory. We can use this memory to store variable those we dont want to lose in no power conditions.
It allows single byte read or wrote at a time, but by writing efficient code we can store and retrieve 16bit variable like unsigned int to/from EEPROM.
WinAVR Gcc compiler provides very rich labrary support for accessing 8bit and 16 bit variable to/from EEPROM.
MegaAVR series controller has three different register to handle all operations related to internal EEPROM.
1. EEAR – EEPROM Address Register
2. EEDR – EEPROM Data Register
3. EECR – EEPROM Control Register
EEDR – EEPROM Data Register
This is an 8-bit register. Data from a location in EEPROM cannot be transferred to location in RAM directly when reading from EEPROM. Similarly, data to be written to EEPROM must be first placed in this register.
EEAR- EEPROM Data Register
Address of location in EEPROM from/to which data is to be read/written has to be first transferred to this register. ATmega32 has 1024 bytes of EEPROM. So this register has two bytes- EEARH (High byte) and EEARL (low byte).
EECR- EEPROM Control Register
This register controls operation of EEPROM. It has 8 bits- each having its special meaning. A programmer must use this register to control operations.
EERE (bit 0) - If written 1, read operation on address specified in EEAR is started.
EEWE (bit 1)- If this bit is written 1 (after setting bit EEWME), write operation on address specified in EEAR is started in next cpu cycle. After write operation is completed, controller will clear this bit automatically.
EEWME (bit 2)- If this bit is written 1, prior to setting EEWE to 1, EEPROM write is started. Other wise write operation is not started.
EERIE (bit 3)- If this bit is written 1, an interrupt is generated when write operation is completed.
Code for 16 bit variables like unsigned int etc.
#include<avr/io.h>
#include<util/delay.h>
#include<compat/deprecated.h>
#include<avr/eeprom.h>
#include<lcd.h>
unsigned int ech EEMEM=0;
void itoa(uint16_t num)
{
unsigned char a,b,c,d,e;
a=num%10;
num=num/10;
b=num%10;
num=num/10;
c=num%10;
num=num/10;
d=num%10;
num=num/10;
e=num%10;
lcd_data(0x30+e);
lcd_data(0x30+d);
lcd_data(0x30+c);
lcd_data(0x30+b);
lcd_data(0x30+a);
}
int main(void)
{
DDRD=0xF4; //SET DATA DIRECTION REGISTER
DDRC=0x30;
PORTD=0x00; //SET 1 for OUTPUT PORT
DDRB=0x00; //SET 0 FOR INPUT PORT
PORTD=0x00;
PORTB=0xFF;
lcd_init();
lcd_cmd(0x01);
while(1)
{
lcd_cmd(0x01);
unsigned int rch=eeprom_read_word(&ech);
itoa(rch);
rch=rch+100;
eeprom_write_word(&ech,rch);
_delay_ms(100);
}
return 0;
}
For more info about avr Library try this project site http://www.nongnu.org/avr-libc/user-manual/
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