Maxim-integrated MAXQ7667 Manual do Utilizador descarregar pdf (Página 151)

8.4.5 LIN Slave

he MAXQ7667 can be used as a LIN slave as shown in Figure 8-5. As the LIN slave, the bus master controls all traffic on the bus.

The slave must synchronize its baud rate to match the master and respond if the master’s identifier is within the slave’s address range.

8.4.5.1 LIN Slave Setup Example

To set the slave mode, the LIN or UART mode select (LUN[1:0]) bits in CNT0 are set for slave mode. To set up the slave mode, the fol-

lowing registers are set as shown.

• Set INIT bit (CNT0.2) to 1 to force LIN into initialization state.

•

Set LUN[1:0] bits (CNT0.1:0) to 0x02 to set LIN slave mode.

•

Set AUT bit (CNT0.3) to 1 to enable automatic checksum.

• Set INE bit (CNT0.4) to 1 to enable interrupts.

•

Set FP[1:0] bits (CNT0.6:5) to 0 to disable r

eceive filter.

• Set WU bit (CNT0.7) to 1 to set the peripheral to wake up.

•

Set CNT1 to 0x00.

• Set CNT2 to 0x00.

• Set SCON to 0x60, i.e., mode 1.

• Clear the INIT bit (CNT0.2) by setting it to 0.

• Set BT (0x0320 sets it for 20kBd).

8.4.5.2 LIN Slave Receiving Protected ID and Break/Sync Example

The LIN slave is now configur

ed and ready to r

eceive and send the br

eak/sync sequence and identifier. The MAXQ processor must

wait until the break/sync sequence has been successfully received.

8-21 __________________________________________________________________________________________________________

MAXQ7667 User’s Guide

Figure 8-5. LIN Bus Slave Communication

LIN BUS MASTER

LIN

BUS

ASTER TASK

LAVE TASK

RITE

EAD/WRITE

READ/WRITECAN BUS

LIN BUS SLAVE

SLAVE TASK

MAXQ7667

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Maxim-integrated MAXQ7667 Manual do Utilizador Página 151