![]() ![]() ![]() The STM32L476 processor is driven by a free running oscillator (MSI clock) which is locked with the 32kHz quartz crystal available on the Nucleo board (LSE clock) and provides very good stability. The user setup can be stored nonvolatile in the microcontroller flash. This way, the device may work as a data bridge between MIDI and RS-232 "worlds". Separately for RS-232 and MIDI operation - the baud rate is configured individually. During RS-232 operation, a special configuration mode gets activated with fast keyboard sequence '+++'. Individual USB Vid/Pid, baud rates and format of input change messages are user configurable. Particularly each LED of the ST-LINK part uses about 10mA! The MIDI and RS-232 driver hardware on this board is powered with 5 Volt. The supply current is in the order of 60-80 mA including the ST-LINK part and 30-35 mA when it is cut off. The Nucleo module scales 5V supply internally down to 3.3V which supplies the complete board except the serial output driver. The device may be operated USB bus powered or with an external power supply as it is supported by the Nucleo hardware. The USB interface is "full speed USB2.0" grade. This feature is switched ON and OFF with a DIP switch.Īssembly of the Nucleo Veroboard (top and solder side view). Input changes trigger user programmable ASCII or MIDI messages merged over the transparent data transfer. Additionally the User Button of the Nucleo works as active pushbutton. Supported by the provided firmware, the new hardware supports up to 9 potentiometers and 7 pushbuttons (or less potentiometers and more pushbuttons, total max.16), which can be be attached at the long brown connectors at the the board edge. A dual red/green LED signals presence of power and data traffic. It works reliably together with standard MIDI inputs, too (modified MIDI OUT wiring see HwDiy manual). It supports standard baud rates up to 115200 Baud plus 31250 Baud(MIDI). Differing from earlier hardware, the USART Tx output is inverted inside the STM32L476 chip and needs no external inverter. ![]() A simple combined MIDI and RS-232 port hardware is provided on the board. The basic mode of operation is "transparent" bidirectional transfer of a byte streamthe device works as a standard MIDI interface or as an external RS-232 port. An STM32F042 interface on a small PCB and another one on a Veroboard are described in parallel at this website. Originally this project was developed for the STM32F042 processor. The additional hardware is built on a Veroboard as a kind of shield (or better say "base board"). USB to MIDI or RS-232 Interface with STM32 Nucleo-L476Ī DIY project is described for for a USB to MIDI (or RS-232) interface based on the STM32 Nucleo-L476 module. ![]()
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