2.10 - SPC (… and SCL/SDA/SCA) [U3 Datasheet]

The SPC terminal is used for manually resetting default values or jumping in/out of flash programming mode.

Power up the U3 with a jumper securely installed from FIO6 to SPC (FIO2 to SCL on U3 1.20/1.21), then remove the jumper and power cycle the device again. This resets all power-up settings to factory default values.

See the LJSelfUpgrade page for information about jumpers to switch between flash mode and normal mode.

Hardware revision 1.20 and 1.21, had terminals labeled SCL, SDA, and/or SCA. On revision 1.20, these terminals did nothing except that SCL is used for the SPC functionality described above. On revision 1.21, these terminals were used for asynchronous functionality, and SCL is used for the SPC functionality described above. Note that these terminals never have anything to do with I²C.