I have a Velleman KA02 audio shield. When I use this shield on an Arduino UNO R3 with this sample code, it works. And by "work" I mean when I interact with the Serial Monitor (by pressing Y, for example), I hear the playback.

However, if I place this audio shield on a Mega 2560 R3, the shield no longer works (pressing Y does nothing). I read about the SPI library, and the document seems to suggest that MISO, MOSI, SCK and SS are different for the Uno vs the Mega. For the Uno,

  • MOSI: 11
  • MISO: 12
  • SCK: 13
  • SS: 10

and the article is consistent with the constants defined in the ISD1700.h file. For the Mega,

  • MOSI: 51
  • MISO: 50
  • SCK: 52
  • SS: 53

I can modify ISD1700.h for use with the Mega easy enough. However, I do not think I can just sit the audio shield right on top of the Mega with the modified code and have it work. I used some (male to female) jumper wires to connect from the Mega pins 50, 51, 52, 53 to the audio shield pins 12, 11, 13, 53 (correspondingly). Additionally, I have jumper wires connecting the power and ground from the Mega to the audio shield. What works is that the audio shield has power and I am able to press the physical buttons on the audio shield to record and playback. What does not work is that when I enter Y in the serial monitor to force a playback, although the character is read and the switch case is reached, the playback never happens.

Any ideas on what I am doing wrong? On the Velleman site, they seem to suggest that this audio shield only works with the Uno, but the Illustrated Assembly Manual says that the audio shield should work with the Mega.

  • put the shield on and it should work. don't change ISD1700 chip(10); to ISD1700 chip(53);
    – Juraj
    Jun 25, 2019 at 4:32

1 Answer 1


Nevermind, I solved it. There's 6 pins located on the Uno and Mega labelled ICSP, and those were the key. I simply connected the MOSI, MISO and SCK pins on the Mega to the audio shield (along with GND and 5V) and also the 10 pin (audio shield) to the 53 pin (Mega) via a male to male jumper. The header code was modified to work with the new values, and now I am able to send character signals via the serial monitor.

  • and why did you change ISD1700 chip(10); to ISD1700 chip(53);? 10 is a good for CS
    – Juraj
    Jun 25, 2019 at 14:58

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