mc68hc708mp16 Freescale Semiconductor, Inc, mc68hc708mp16 Datasheet - Page 313

• Manufacturer Part Number: mc68hc708mp16
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

14.8.5 SCI Status Register 2
MC68HC708MP16
Freescale Semiconductor
—
Rev. 3.1
Address:
SCI status register 2 contains flags to signal these conditions:
BKF — Break Flag Bit
RPF —Reception in Progress Flag Bit
Reset:
Read:
Write:
•
•
This clearable, read-only bit is set when the SCI detects a break
character on the PTF4/RxD pin. In SCS1, the FE and SCRF bits are
also set. In 9-bit character transmissions, the R8 bit in SCC3 is
cleared. BKF does not generate a CPU interrupt request. Clear BKF
by reading SCS2 with BKF set and then reading the SCDR. Once
cleared, BKF can become set again only after logic 1s again appear
on the PTF4/RxD pin followed by another break character. Reset
clears the BKF bit.
This read-only bit is set when the receiver detects a logic 0 during the
RT1 time period of the start bit search. RPF does not generate an
interrupt request. RPF is reset after the receiver detects false start bits
(usually from noise or a baud rate mismatch, or when the receiver
detects an idle character. Polling RPF before disabling the SCI
module or entering stop mode can show whether a reception is in
progress.
Serial Communications Interface Module (SCI)
1 = Break character detected
0 = No break character detected
1 = Reception in progress
0 = No reception in progress
Break character detected
Incoming data
$003C
Bit 7
0
Figure 14-12. SCI Status Register 2 (SCS2)
= Unimplemented
6
0
5
0
Serial Communications Interface Module (SCI)
4
0
3
0
2
0
BKF
1
0
Technical Data
Bit 0
RPF
0
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