mc68hc908gr8vp Freescale Semiconductor, Inc, mc68hc908gr8vp Datasheet - Page 178

• Manufacturer Part Number: mc68hc908gr8vp
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Serial Communications Interface (SCI)
ILIE — Idle Line Interrupt Enable Bit
TE — Transmitter Enable Bit
RE — Receiver Enable Bit
RWU — Receiver Wakeup Bit
SBK — Send Break Bit
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This read/write bit enables the IDLE bit to generate SCI receiver CPU interrupt requests. Reset clears
the ILIE 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 PE2/TxD pin. If software clears the TE bit, the transmitter completes any
transmission in progress before the PE2/TxD returns to the idle condition (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.
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.
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.
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 = IDLE enabled to generate CPU interrupt requests
0 = IDLE not enabled to generate CPU interrupt requests
1 = Transmitter enabled
0 = Transmitter disabled
1 = Receiver enabled
0 = Receiver disabled
1 = Standby state
0 = Normal operation
1 = Transmit break characters
0 = No break characters being transmitted
Writing to the TE bit is not allowed when the enable SCI bit (ENSCI) is clear.
ENSCI is in SCI control register 1.
Writing to the RE bit is not allowed when the enable SCI bit (ENSCI) is
clear. ENSCI is in SCI control register 1.
Do not toggle the SBK bit immediately after setting the SCTE bit. Toggling
SBK before the preamble begins causes the SCI to send a break character
instead of a preamble.
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
NOTE
NOTE
NOTE
Freescale Semiconductor