AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) buf;
AT91C_BASE_PDC_SSC->PDC_RCR = len;
AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) buf;
AT91C_BASE_PDC_SSC->PDC_RNCR = len;
AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTEN;
AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) buf;
AT91C_BASE_PDC_SSC->PDC_RCR = len;
AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) buf;
AT91C_BASE_PDC_SSC->PDC_RNCR = len;
AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTEN;