Esp32_radio.ino :::: shutdown_pin >= 0 ::::

[pippo-75]

Goodmorning, here following there are some code excerpts from his project Esp32_radio.ino There are 3 code line where < if ( shutdown_pin >= 0 ) > has been used:

void VS1053::begin() { ......................................................................... if ( shutdown_pin >= 0 ) // Shutdown in use? { pinMode ( shutdown_pin, OUTPUT ) ; digitalWrite ( shutdown_pin, HIGH ) ; // Shut down audio output } .........................................................................

void VS1053::startSong() { sdi_send_fillers ( 10 ) ; if ( shutdown_pin >= 0 ) // Shutdown in use? { digitalWrite ( shutdown_pin, LOW ) ; // Enable audio output } }

void VS1053::stopSong() { ......................................................................... sdi_send_fillers ( 2052 ) ; if ( shutdown_pin >= 0 ) // Shutdown in use? { digitalWrite ( shutdown_pin, HIGH ) ; // Disable audio output } .........................................................................

Now, if I understand correctly, shutdown_pin (as stated) is a Digital Pin (VS1053::begin), so its value can be read as HIGH / LOW (1/0) using digitalRead or reading the relative "bit" somewhere in the register. Also, in any case, if we comparing a 'value' simply if it's -Equal to- or -Higher than- 0 (zero), as result we always get >>true<<

Please correct me if I'm wrong, but I think it's a typo.

Anyway, thanks for Your time and this great project.

[Edzelf]

No, shutdown_pin is a variable defining the GPIO to be used for shutdown of the amplifier. A negative value is assigned to it if the shutdown function is not used. Shutdown is an output bit, so its value is never read by digitalRead().

[pippo-75]

Hello, obviously I'm wrong: I'm sorry. Here following an excerpt where >> shutdown_pin << is declared:

//** // VS1053 class definition. * //** class VS1053 { private: uint8_t cs_pin ; // Pin where CS line is connected uint8_t dcs_pin ; // Pin where DCS line is connected uint8_t dreq_pin ; // Pin where DREQ line is connected _uint8_t shutdownpin ; // Pin where the shutdown line is connected uint8_t curvol ; // Current volume setting 0..100% const uint8_t vs1053_chunk_size = 32 ; // SCI Register

The thing that I don't understand is: it's really declared as unsigned or, instead, I've to look somewhere in the code ?

Please, excuse me for my insistence and have a good day.

[Edzelf]

Yes, it should be declared as a int8_t. Fixed.