Hi all!
I like to control my Seq V4 (LPC1769) with my MidiboxNG (STM32F4) via Midi.
Is it correct if i connect
LPC1769 Core P2.1 to STM32F4 Core PA2
and
LPC1769 Core P2.0 to STM32F4 Core PA3?
Thanks for your advice.
Marxon
…it is correct, if you want to connect MIDI-Port1 (LPC) to MIDI-Port1 (STM32F4), so you should be able to receive midi with your lpc from the stm32 and receive with your stm32 from the lpc…
mOnO
Ok. Thanks for your reply mOnO!
Since STM32F4 outputs the MIDI Tx signals in open drain mode, it makes sense to add a 1k pull-up resistor to this pin.
Not relevant for the Tx output of LPC17, since there it’s configured in push-pull mode (due to a hardware imperfection)
Best Regards, Thorsten.
Hi again!
I have another question about the STM32F4 midi in/out:
How do i connect external midi devices?
Can I use this circuit?
Best regards
Marxon
Yes - I am not sure about the pin names (haven’t checked them), but the schematic is the standard MIDI schematic to be used!
Ok thank you ilmenator!
Does it make a difference if i connect
the optocuppler Pin 6 to 5V instead of 3,3V
and if i use a 5,6k instead of a 4,7k resistor
like in older schematics?
The resistors’ values depend on the voltage you apply to the optocoupler. The voltage usually depends on the microcontroller you use. However, the inputs in the MCUs used by MIDIbox should all tolerate 5V.
OK i might have known it… 
Thanks for clarification.