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Topic: DCC Arduine design oversight (Read 1 time) previous topic - next topic

gharryh

The attached file contains a design voor a DCC controller shield to accomodate a NANO or 328 with boorloader.
As this is my first design maybe someone could have a look and see if i stumbled into some pitfall.

dpharris

Hey!  Tell us more.   Scale, how to use etc.  Looks interesting :-)

David
Dr. David Harris
OpenLCB Dev Team

CrossRoads

The SD card may not be reliable with just voltage divider for signal level conversion.
Recommend add a buffer powered from 3.3v with 5v tolerant inputs, such as used here:

http://www.ladyada.net/make/logshield/design.html
http://www.mouser.com/ProductDetail/Texas-Instruments/SN74AHC125N/?qs=sGAEpiMZZMuiiWkaIwCK2UHhUsuHvyUOwPyIialPONc%3d
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

gharryh


Hey!  Tell us more.   Scale, how to use etc.  Looks interesting :-)

David


The idea is to have a controller like the Märklin Turntable controller butr then for DCC and to be used in a bigger scale such as O and 1.
I allready worked for some years on this idea but with the Arduine programming became a lot easyier then with a PIC and bare AVR.

There's no blog yet on the progress on the project but there will be one in the near futher.

gharryh


The SD card may not be reliable with just voltage divider for signal level conversion.

If i look here: http://www.mikroe.com/pdf/mmc_proto_schematic_v100.pdf
and here : http://www.kronosrobotics.com/Projects/MMC.pdf then it should work.

The sd card is not intended for heavy use. Maybe only once.
If i can find a system to load the EEPROM true a serial interface from windows then the SD wound be used at all.

Grumpy_Mike

Yes but you will find that these are just one off experiences. Lady Ada sells a wave shield and they went from voltage dividers in the early versions to level converters because they came across so much trouble.

gharryh

#6
Dec 14, 2011, 10:11 am Last Edit: Dec 14, 2011, 10:53 pm by gharryh Reason: 1
I am now testing if using TerraTerm terminal i can upload a file to the EEPROM.
Must see is the Arduine Serial.read() can handle this.

In the process i have allready removed all SD card related components. See the file attached.

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