Datasheet

VS1053b Datasheet
10 OPERATION
10.9 SPI Boot
If GPIO0 is set with a pull-up resistor to 1 at boot time, VS1053b tries to boot from external SPI
memory.
SPI boot redefines the following pins:
Normal Mode SPI Boot Mode
GPIO0 xCS
GPIO1 CLK
DREQ MOSI
GPIO2 MISO
The memory has to be an SPI Bus Serial EEPROM with 16-bit or 24-bit addresses. The serial
speed used by VS1053b is 245 kHz with the nominal 12.288 MHz clock. The first three bytes
in the memory have to be 0x50, 0x26, 0x48.
10.10 Real-Time MIDI
If GPIO0 is low and GPIO1 is high during boot, real-time MIDI mode is activated. In this mode
the PLL is configured to 4.0×, the UART is configured to the MIDI data rate 31250 bps, and
real-time MIDI data is then read from UART and SDI. Both input methods should not be used
simultaneously. If you use SDI, first send 0x00 and then send the MIDI data byte.
EarSpeaker setting can be configured with GPIO2 and GPIO3. The state of GPIO2 and GPIO3
are only read at startup.
Real-Time MIDI can also be started with a small patch code using SCI.
Note: The real-time MIDI parser in VS1053b does not know how to skip SysEx messages. An
improved version can be loaded into IRAM if needed.
Version: 1.22, 2014-12-19 59