R11 belongs to CAN bus J18 its R9 that dosn’t hurt if already soldered. And SA is SD on the schematic http://ucapps.de/mbhp/mbhp_core_lpc17.pdf
this is the corrected text to copy:
A second IIC port, which can also be used as an additional MIDI IN/OUT port (MIDI IN4/OUT4) if enabled in MIOS32 (add “#define MIOS32_UART_NUM 4” to the mios32_config.h file).
MIDI IN4 will be available on the J4B.SC. If a 6N138 based optocoupler circuit should be connected, replace the 2.2k pull-up R10 by 1k, or add a second 2.2k in parallel to get 1.1k effectively.
MIDI OUT4 will be available on the J4B.SD pin, it isn’t required to remove R9 if already soldered - it doesn’t hurt.
I hope this is helpful and correct.
best regards
novski
