Use Arduino to program Arachnid EEPROM

[Kastor]

Hello


I am building a Arachnid pedal, and I want to be able to re-write the eeprom without removing it from its socket every time.
So I figured two ways to realize that.
a) Just solder 2 cables to the SDA and SCL pin to the eeprom, and let the board power it. So the Arduino just sends the data.
b) solder 8 cables to the eeprom and connect them all to the arduino.

You think any of those is better somehow ?

Regards

 

[Robert]

The SDA and SCL lines are connected to the FV-1 and shouldn't exceed 3.3V so you'll need a way to lower the signal levels. Can the Arduino operate on 3.3V?

Aside from SDA/SCL/VCC all other pins of the EEPROM go to ground, so there's no reason to connect all 8 pins.

 

[Kastor]

It can't operate on 3.3 Volts directly, but I can use a level shifter board so thats no problem.

Still the question is, should I use the power from the Arachnid board or from the Arduino to power the eeprom

 

[Robert]

Unless you do some trace modifications you'll be powering the EEPROM, FV-1, and the ATTINY (if you're using the V1 Arachnid). Can the Arduino supply enough current? This would be the only important factor.

I suppose for convenience it would be nice to not need pedal power connected for a quick EEPROM flash, but in practice it's not that much of an inconvenience and you'll likely want to audibly verify that the flash was successful anyway.

The USB FV-1 Dev board powers the EEPROM from the pedal, not the USB port.

 

[Kastor]

I am not sure about the current of the Arduino, IIRC it wasn't too much. So yeah I'll use the pedal power.
Thanks so much for your help !

 

[fontoponto]

Just a curious question: if I add a logic level converter then I could just add SCL and SDA from the arduino to for example Arachnid and leave it connected right?
Like here: https://forum.pedalpcb.com/threads/sourcing-a-ch341a.5528/#post-60271
Without the converter it does not work. In the link he uses an Arduio nano as far as I can see but these have 5V pins not 3,3 like some Minis.
Edit: I am able to write to the EEPROM with my Arduino on a breadboard. The chip is capable of handling the 5V on SDA/SCL but not when I just hook up the SCL/SDA wires to the Arachnid.

 

[anonymouseca73]

Can AMS1117 or similar 1117 LDO be used as a replacement for 78L33 to achieve 3.3V?
I found a thread with conflicting opinions on here: http://www.spinsemi.com/forum/viewtopic.php?t=868
I was wondering how well it can perform in the context of PedalPCB builds.