Freescale Semiconductor MC68HC908MR32 - Manual (Page 172)

Serial Communications Interface Module (SCI)
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
172 Freescale Semiconductor
SCRIE — SCI Receive Interrupt Enable Bit
This read/write bit enables the SCRF bit to generate SCI receiver CPU interrupt requests. Setting the
SCRIE bit in SCC3 enables the SCRF bit to generate CPU interrupt requests. Reset clears the SCRIE
bit.
1 = SCRF enabled to generate CPU interrupt
0 = SCRF not enabled to generate CPU interrupt
ILIE — Idle Line Interrupt Enable Bit
This read/write bit enables the IDLE bit to generate SCI receiver CPU interrupt requests. Reset clears
the ILIE bit.
1 = IDLE enabled to generate CPU interrupt requests
0 = IDLE not enabled to generate CPU interrupt requests
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
NOTE
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.