NXP Semiconductors freescale K51 Series Reference Manual

6. Write to set up interrupt enable bits desired (C3[ORIE], C3[NEIE], C3[PEIE], andC3[FEIE])7. Write to set C4[MAEN1] = 0 and C4[MAEN2] = 0.8. Write to C5 register and configure DMA control register bits as desired forapplication.9. Write to set C7816[INIT] = 1,C7816[ TTYPE] = 0, 7C7816[ISO_7816E] = 1.Program C7816[ONACK] and C7816[ANACK] as desired.10. Write to IE7816 register to set interrupt enable parameters as desired.11. Write to ET7816 register and set as desired.12. Write to set C2[ILIE] = 0, C2[RE] = 1, C2[TE] = 1, C2[RWU] = 0 and C2[SBK] = 0.Setup interrupt enables C2[TIE], C2[TCIE] and C2[RIE] as desired.At this time the UART will start listening for an initial character. Once identified it willautomatically adjust the S2[MSBF], C3[TXINV] and S2[RXINV] bits. The softwareshould then receive and process an answer to reset. Upon processing the answer to resetsoftware should write to set C2[RE] = 0 and C2[TE] = 0. Software should then adjust7816 specific and UART generic parameters to match and configuration data that wasreceived during the answer on reset period. Once the new settings have been programmed(including the new baud rate and C7816[TTYPE]) the C2[RE] and C2[TE] can be re-enabled as required.48.8.2.1 Transmission procedure for (C7816[TTYPE] = 0)When the protocol selected is C7816[TTYPE] = 0, it is assumed that the software has aprior knowledge of who should be transmitting and receiving. Hence, no mechanism isprovided for automated transmission/receipt control. Software should monitor theS1[TDRE] flag (or configure for an interrupt) and provide additional data fortransmission as appropriate. Additionally, software should set C2[TE] = 1 and controlTXDIR whenever it is the UART's turn to transmit information. For ease of monitoring itis suggested that only data to be transmitted until the next receiver/transmit switch overbe loaded into the transmit buffer/FIFO.Chapter 48 Universal Asynchronous Receiver/Transmitter (UART)K51 Sub-Family Reference Manual, Rev. 6, Nov 2011Freescale Semiconductor, Inc. 1295