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| VS1053B Datasheet, PDF (56/79 Pages) List of Unclassifed Manufacturers – Ogg Vorbis/MP3/AAC/WMA/MIDI AUDIO CODEC | |||
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VLSI
Solution y
VS1053b preliminary
VS1053B
9. OPERATION
9.9 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 redeï¬nes the following pins:
Normal Mode
GPIO0
GPIO1
DREQ
GPIO2
SPI Boot Mode
xCS
CLK
MOSI
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 ï¬rst three bytes in the memory have
to be 0x50, 0x26, 0x48.
9.10 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 conï¬gured to 4.0Ã, the UART is conï¬gured 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, ï¬rst send 0xff and then send the MIDI data byte.
EarSpeaker setting can be conï¬gured 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 0.5, 2007-12-03
56
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