MC908MR32CFUE 参数 Datasheet PDF下载

Serial Communications Interface Module (SCI)

TE — Transmitter Enable Bit

Setting this read/write bit begins the transmission by sending a preamble of 10

or 11 1s from the transmit shift register to the PTF5/TxD pin. If software clears

the TE bit, the transmitter completes any transmission in progress before the

PTF5/TxD returns to the idle condition (logic 1). Clearing and then setting TE

during a transmission queues an idle character to be sent after the character

currently being transmitted. Reset clears the TE bit.

1 = Transmitter enabled

0 = Transmitter disabled

NOTE:

Writing to the TE bit is not allowed when the enable SCI bit (ENSCI) is clear. ENSCI

is in SCI control register 1.

RE — Receiver Enable Bit

Setting this read/write bit enables the receiver. Clearing the RE bit disables the

receiver but does not affect receiver interrupt flag bits. Reset clears the RE bit.

1 = Receiver enabled

0 = Receiver disabled

Writing to the RE bit is not allowed when the enable SCI bit (ENSCI) is clear.

ENSCI is in SCI control register 1.

RWU — Receiver Wakeup Bit

This read/write bit puts the receiver in a standby state during which receiver

interrupts are disabled. The WAKE bit in SCC1 determines whether an idle input

or an address mark brings the receiver out of the standby state and clears the

RWU bit. Reset clears the RWU bit.

1 = Standby state

0 = Normal operation

SBK — Send Break Bit

Setting and then clearing this read/write bit transmits a break character followed

by a 1. The 1 after the break character guarantees recognition of a valid start

bit. If SBK remains set, the transmitter continuously transmits break characters

with no 1s between them. Reset clears the SBK bit.

1 = Transmit break characters

0 = No break characters being transmitted

NOTE:

Do not toggle the SBK bit immediately after setting the SCTE bit. Toggling SBK too

early causes the SCI to send a break character instead of a preamble.

Data Sheet

186

MC68HC908MR32 • MC68HC908MR16 — Rev. 6.0

Serial Communications Interface Module (SCI)

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