
I/O Registers
MC68HC08LK60 MC68HC908LK60 Advance Information Data Sheet, Rev. 1.1
Freescale Semiconductor
139
SBK — Send break bit
Setting and then clearing this read/write bit transmits a break character followed by a logic 1. The
logic 1 after the break character guarantees recognition of a valid start bit. If SBK remains set, the
transmitter continuously transmits break characters with no logic 1s between them.
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.
12.9.3 SCI Control Register 3
SCI control register 3:
Stores the ninth SCI data bit received and the ninth SCI data bit to be transmitted
Enables these interrupts:
–
Receiver overrun interrupts
–
Noise error interrupts
–
Framing error interrupts
–
Parity error interrupts
R8 — Received bit 8
When the SCI is receiving 9-bit characters, R8 is the read-only ninth bit (bit 8) of the received character.
R8 is received at the same time that the SCDR receives the other eight bits.
When the SCI is receiving 8-bit characters, R8 is a copy of the eighth bit (bit 7).
T8 — Transmitted bit 8
When the SCI is transmitting 9-bit characters, T8 is the read/write ninth bit (bit 8) of the transmitted
character. T8 is loaded into the transmit shift register at the same time that the SCDR is loaded into
the transmit shift register.
DMARE — DMA receive enable bit
This bit enables the DMA to service SCI receiver DMA service requests generated by the SCRF bit.
requests.
1 = DMA enabled to service SCI receiver DMA service requests generated by the SCRF bit
(SCI receiver CPU interrupt requests disabled)
0 = DMA not enabled to service SCI receiver DMA service requests generated by the SCRF bit
(SCI receiver CPU interrupt requests enabled)
CAUTION
There is no DMA on this device. This bit should be cleared.
Address:
$0015
Bit 7
654321
Bit 0
Read:
R8
T8
DMARE
DMATE
ORIE
NEIE
FEIE
PEIE
Write:
Reset:
U
000000
= Unimplemented
U = Unaffected
Figure 12-13. SCI Control Register 3 (SCC3)