Home-made Double Layer ATmega32 PCB for RS232/RS422 Communication testing

Hi guys,
after making my single layer starter's kit M32_Card, I was looking for making a double layer M32 PCB at home. So, here is my attempt to make it. Well, it didn't turn out to be as difficult as I had thought it to be earlier. I had to dump one PCB before making this one as the top-layer routine was not solder-friendly!!

I've made this one mainly for an application where RS232 & RS422 testing was required. It uses MAX232 & MAX488 ICs from for those serial communication. Selection between RS232 & RS422 is through jumpers. The board is using ATmega32 controller, just like my single layer pcb. It also has 4x4 matrix keyboard, an LCD interface, ADC connector, SPI connector (for In System Programming), a reset switch and an LED for beginner's programming. It operates with the standard 12v DC adapter.

Here is the schematic (click on the image to enlarge):


There is a small mistake here in the schematic, the RX/TX pin connections in the RS232 connector are swapped, which I found while testing the PCB. So, I had to correct it by cutting those two tracks and placing jumpers. After the correction, the communication with PC was established. The schematic is similar to the M32_Card, accept that I've removed the RTC DS1307 and placed the MAX488. Also, the individual push buttons are replaced with the 16 key matrix key-board.
Click here to get more info and for downloading code to interface the 4x4 matrix keyboard shown here

The PCB etching is done with Ferric Chloride. In making the double layer PCB, as I don't have any PTH (printed through holes) facility, I've put small pieces of single core wire into the holes and soldered both sides. Check out the top and bottom layers here














If you have an application where the circuit can not be contained in a single layer, a home-made double layer PCB is worth a try!!

Thanks!
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ccd@dharmanitech.com

DIY AVR Programmers

Hi guys,
for those who are trying to make AVR kit at home, an AVR programmer which can be simple to make will be really useful, as it'll avoid buying the programmer!! Here I'm giving a few webpage links on how to make a programmers yourself.

- Here is a simple AVR serial programmer, works with PC serial port, easy to make:










For complete info check out the webpage:
AVR Serial programmer from Extremeelectronics.co.in

- For using the serial programmer discussed above, a driver software is required to be installed in your pc. Download it from here:
PonyProg : AVR serial programmer

- If you are using a laptop which doesn't have serial port then you can buy a low-cost AVR USB programmer shown in the figure. Visit this webpage for buying it:

AVR USB Programmer

Here is one more option for buying a cheap USB programmer for AVR at around $15 cost:
AVR USB Programmer lite

And if you want to make an USB programmer yourself, check out here an easy to make AVR USB programmer:
DIY AVR USB Programmer

- Atmel has given a detailed document on design of In-System Programmer for AVR. It inclludes the schematic of the programmer. Download this pdf document from here:
In-System Programmer for AVR, from Atmel

- For those who like pc parallel port better, here is a page containing data on how to make a parallel port AVR programmer along with the download for the pc:
Parallel port programmer for AVR

- Here is another parallel port programmer from AVRdude:
AVRdude parallel port programmer

- One more parallel port programmer using AT90S1200 microcontroller, with schematic and the .asm file. (Note: it need a pre-programmed AT90S1200 IC). Check out more on the webpage:
Psychogenic PPI AVR Programmer

- Apart from these, some more free designs are there, you'll find them by googling!! And if you want to buy, there are plenty of them available!!!

Hope this info is useful for your project work..
Thanks!

Make-Yourself ATmega32 Starter's Kit with LCD, I2C, SPI, RTC, ADC interfaces

Hi friends,
here is my home-made kit of ATmega32 microcontroller interfacing. The ATmega32 controller is rich with features like onboard 32kB in-System programmable flash, 1 KB EEPROM, 2KB SRAM, 10bit ADC (8 channel), SPI bus inteface, TWI (compatible with I2C bus) interface, an USART, analog comparator, etc. That's why I've selected it to load my kit with all those features.

This M32 card is having an LCD inteface with contrast adjustment, an RS232 port for connecting with PC, a connector for 8 analog voltage inputs to measure by ADC, a Real Time Clock IC DS1307 from maxim with battery back-up, four general purpose keys, two keys for generating interrupts and an LED.
The circuit can be powered by an easily available 12v DC adapter. The voltage regulator IC 7805 used to convert the input into regulated 5v supply.

See below the kit in powered on condition and the schematic (click to enlarge the images)













The PCB is completely home-made, using the etching technique with the Ferric Chloride chemical. If you want to know how to make a PCB yourself from your layout, visit following webpage, it's really helpful:

http://electrons.psychogenic.com/modules/arms/art/10/pcb_howto.php

The schematic and layout of the M32_card shown here are prepared using EAGLE. It's a single layer board for making the home-preparation easy. Check out the bottom layer and the layouts in the pics below:












The software for the ATmega32 controller is written using imageCraft AVR compiler. The software contains code for LCD interface, use of RTC and communication with PC with RS232 port. Using the Hyper terminal in windows, the functionality of the kit can be checked, as I've mentioned in my previous post of RTC_EEPROM interface with ATmega128.
Sown below are the pics of RTC circuit in test and related screen shot of the hyper terminal while interacting with the M32_Card

















Here is Proteus ISIS Simulation:



The complete source code files including new addition of ADC (check out Here) can be downloaded below.


Download
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Source code
PCB files (in PDF & EAGLE formats)Proteus Simulation Model

Datasheets:

ATmega32 DS1307 MAX232

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ccd@dharmanitech.com