8-14
8XC196NP, 80C196NU USER’S MANUAL
The receiver checks for a valid stop bit. Unless a stop bit is found within the appropriate time, the
framing error (FE) bit in the SP_STATUS register is set. When the stop bit is detected, the data
in the receive shift register is loaded into SBUF_RX and the receive interrupt (RI) flag is set. If
this happens before the previous byte in SBUF_RX is read, the overrun error (OE) bit is set.
SBUF_RX always contains the latest byte received; it is never a combination of the last two bytes.
SP_STATUS
Address:
Reset State:
1FB9H
0BH
The serial port status (SP_STATUS) register contains bits that indicate the status of the serial port.
7
0
RPE/RB8
RI
TI
FE
TXE
OE
—
—
Bit
Number
Bit
Mnemonic
Function
7
RPE/RB8
Received Parity Error/Received Bit 8
RPE is set if parity is disabled (SP_CON.2 = 0) and the ninth data bit
received is high.
RB8 is set if parity is enabled (SP_CON.2 = 1) and a parity error
occurred.
Reading SP_STATUS clears this bit.
6
RI
Receive Interrupt
This bit is set when the last data bit is sampled. Reading SP_STATUS
clears this bit.
This bit need not be clear for the serial port to receive data.
5
TI
Transmit Interrupt
This bit is set at the beginning of the stop bit transmission. Reading
SP_STATUS clears this bit.
4
FE
Framing Error
This bit is set if a stop bit is not found within the appropriate period of
time. Reading SP_STATUS clears this bit.
3
TXE
SBUF_TX Empty
This bit is set if the transmit buffer is empty and ready to accept up to two
bytes. It is cleared when a byte is written to SBUF_TX.
2
OE
Overrun Error
This bit is set if data in the receive shift register is loaded into SBUF_RX
before the previous bit is read. Reading SP_STATUS clears this bit.
1:0
—
Reserved. These bits are undefined.
Figure 8-8. Serial Port Status (SP_STATUS) Register
Содержание 80C196NU
Страница 1: ...8XC196NP 80C196NU Microcontroller User s Manual...
Страница 2: ...8XC196NP 80C196NU Microcontroller User s Manual August 1995 Order Number 272479 002...
Страница 18: ...1 Guide to This Manual...
Страница 19: ......
Страница 31: ......
Страница 32: ...2 Architectural Overview...
Страница 33: ......
Страница 48: ...3 Advanced Math Features...
Страница 49: ......
Страница 56: ...4 Programming Considerations...
Страница 57: ......
Страница 72: ...5 Memory Partitions...
Страница 73: ......
Страница 106: ...6 Standard and PTS Interrupts...
Страница 107: ......
Страница 144: ...7 I O Ports...
Страница 145: ......
Страница 165: ......
Страница 166: ...8 Serial I O SIO Port...
Страница 167: ......
Страница 183: ......
Страница 184: ...9 Pulse width Modulator...
Страница 185: ......
Страница 196: ...10 Event Processor Array EPA...
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Страница 225: ......
Страница 226: ...11 Minimum Hardware Considerations...
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Страница 239: ......
Страница 240: ...12 Special Operating Modes...
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Страница 255: ......
Страница 256: ...13 Interfacing with External Memory...
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Страница 303: ......
Страница 304: ...A Instruction Set Reference...
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Страница 373: ......
Страница 374: ...B Signal Descriptions...
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Страница 390: ...C Registers...
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Страница 447: ......
Страница 448: ...Glossary...
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Страница 458: ...Index...
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