For just blinking a LED why don't you use GPIO ?
You can toggle LED by connecting to GPIF II interface line and drive alternateGPIF II with a byte value with alternate 0x00 and 0xFF.
For I2C /SPI it is not possible to blink it continously .
May I know what is the need of connector?How may LEDs that you want to use?
You can connect LED directly to the Data line if you want to connect to the GPIF II interface.