VIC slots used for the LPC2148 define name e g gps UART1_VIC_SLOT e g modem SPI1_VIC_SLOT SPI1 in mcu_periph spi_arch c or spi_slave_hs_arch c(and some others not using the SPI peripheral yet..) I2C0_VIC_SLOT 8 mcu_periph/i2c_arch.c I2C1_VIC_SLOT 9 mcu_periph/i2c_arch.c USB_VIC_SLOT 10 usb