mc68hc908gr8vp Freescale Semiconductor, Inc, mc68hc908gr8vp Datasheet - Page 182

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

Serial Communications Interface (SCI)
18.8.5 SCI Status Register 2
SCI status register 2 contains flags to signal the following conditions:
BKF — Break Flag Bit
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This clearable, read-only bit is set when the SCI detects a break character on the PE1/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 1s again appear on
the PE1/RxD pin followed by another break character. Reset clears the BKF bit.
1 = Break character detected
0 = No break character detected
Break character detected
Incoming data
Address:
Reset:
Read:
Write:
BYTE 1
BYTE 1
$0017
Bit 7
0
0
READ SCS1
READ SCDR
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
SCRF = 1
Figure 18-14. SCI Status Register 2 (SCS2)
= Unimplemented
OR = 0
BYTE 1
Figure 18-13. Flag Clearing Sequence
6
0
0
READ SCDR
READ SCS1
BYTE 2
BYTE 2
DELAYED FLAG CLEARING SEQUENCE
SCRF = 1
NORMAL FLAG CLEARING SEQUENCE
BYTE 1
OR = 0
5
0
0
READ SCDR
READ SCS1
SCRF = 1
4
0
0
BYTE 2
OR = 0
3
0
0
BYTE 3
BYTE 3
2
0
0
READ SCDR
READ SCDR
READ SCS1
READ SCS1
SCRF = 1
SCRF = 1
BYTE 3
BYTE 3
OR = 1
OR = 0
BKF
1
0
BYTE 4
BYTE 4
Freescale Semiconductor
Bit 0
RPF
0