following diagram shows the location of these pins and their functions. Feel free to use them in your
project:
In addition to the rotary encoder header, there are several additional pins available on the six-pin
ISP (In-System Programming) connector. This connector is normally used to perform bare-metal
programming of the ATmega microprocessor (such as replacing the bootloader) using a compatible
ISP
. You can use these pins for your own purposes, but
be aware
that the SPI
interface (the MOSI, MISO and SCK pins) is already heavily used by the playback software to move
data from the micro-SD card to the VS1053B chip.
But all is not lost! If you want to use the SPI interface for other purposes, such as driving an
addressable LED string, you can do so if you're careful. Bill Porter's MP3 Player library will let you
use the SPI pins
between audio transfers
, as long as you're quick about it and release the SPI port
in time for the next data transfer to take place. (If you don't, the VS1053B will run out of buffered
data and "starve", causing a gap or glitch in the playback.) See Bill's
for instructions
on how to do this, and have fun!
Troubleshooting
If you don't hear anything, hopefully the following list will help you find the problem.
Serial debugging
A big troubleshooting tip for almost any issue, is that both the "Trigger" and "Player" sketches have
an option in the code to send debugging output to the serial port. When this is turned on ("true"),
text messages will be output to the serial port describing what the board is doing at any given time,
as well as any problems it finds. Serial debugging is turned on by default in the "Player" sketch. To
turn on serial debugging in the "Trigger" sketch, follow these steps:
* Open the "Trigger" sketch in the Arduino IDE (see the programming page for more information)
* There will be a line near the top that says "debugging = false"
* Change "false" to "true"
* Upload the modified sketch
* In the IDE, turn on the Serial Monitor window
* Set the baud rate to 9600
Page 23 of 28
