spi_wr8_ack
spi_wr8_ack(udc, reg, val, 0);
spi_wr8_ack(udc, MAX3420_REG_EP0BC, 2, 1);
spi_wr8_ack(udc, MAX3420_REG_EPIRQ, OUT0DAVIRQ, 1);
spi_wr8_ack(udc, MAX3420_REG_EPIRQ, OUT1DAVIRQ, 1);