7751 Group User’s Manual
7–51
SERIAL I/O
7.4 Clock asynchronous serial I/O (UART) mode
7.4.7 Process on detecting error
Errors listed below can be detected in the UART mode:
●
Overrun error
An overrun error occurs when the next data is prepared in the UARTi receive register with the receive
completion flag = “1” (that is, data present in the UARTi receive buffer register) and that data is transferred
to the UARTi receive buffer register. In other words, when the next data is prepared before the contents
of the UARTi receive buffer register is read out, an overrun error occurs. When an overrun error occurs,
the next receive data is written into the UARTi receive buffer register, and the UARTi receive interrupt
request bit is not changed.
●
Framing error
A framing error occurs when the number of detected stop bits does not match the number of stop bits set.
(The UARTi interrupt request bit becomes “1.”)
●
Parity error
A parity error occurs when the sum of “1”s in the parity bit and character bits does not match the number
of “1”s set. (The UARTi interrupt request bit becomes “1.”)
Each error is detected when data is transferred from the UARTi receive register to the UARTi receive buffer
register, and the corresponding error flag is set to “1.” Furthermore, when any of the above errors occurs,
the error sum flag is set to “1.” Accordingly, the error sum flag informs the user whether any error has
occurred or not.
The overrun error flag is cleared to “0” by clearing the receive enable bit to “0.”
The framing error flag and the parity error flag are cleared to “0” by reading the contents of the UARTi
receive buffer register low-order byte or clearing the receive enable bit to “0.” The error sum flag is cleared
to “0” by clearing the all error flags, which are overrun, framing, and parity.
When errors occur during reception, initialize the error flags and the UARTi receive buffer register, and
then perform reception again. When it is necessary to perform retransmission owing to an error which
occurs in the receiver side, set the UARTi transmit buffer register again, and then starts transmission
again.
The method of initializing the UARTi receive buffer register and that of setting the UARTi transmit buffer
register again are described below.
(1) Method of initializing UARTi receive buffer register
➀
Clear the receive enable bit to “0” (reception disabled).
➁
Set the receive enable bit to “1” again (reception enabled).
(2) Method of setting UARTi transmit buffer register again
➀
Clear the serial I/O mode select bits to “000
2
” (serial I/O ignored).
➁
Set the serial I/O mode select bits again.
➂
Set the transmit enable bit to “1” (transmission enabled), and set the transmit data to the UARTi
transmit buffer register.
Summary of Contents for 7700 FAMILY
Page 2: ...MITSUBISHI 16 BIT SINGLE CHIP MICROCOMPUTER 7700 FAMILY 7751 SERIES 7751 Group User s Manual...
Page 11: ...Table of Contents viii 7751 Group User s Manual MEMORANDUM...
Page 157: ...TIMER B 6 28 7751 Group User s Manual 6 5 Pulse period pulse width measurement mode MEMORANDUM...
Page 245: ...7751 Group User s Manual 8 36 A D CONVERTER Precautions when using A D converter MEMORANDUM...
Page 265: ...7751 Group User s Manual WAIT MODE 11 6 11 3 Precautions for Wait mode MEMORANDUM...
Page 289: ...CONNECTION WITH EXTERNAL DEVICES 12 4 Hold function 7751 Group User s Manual 12 24 MEMORANDUM...
Page 290: ...CHAPTER 13 RESET 13 1 Hardware reset 13 2 Software reset...
Page 302: ...CHAPTER 14 CLOCK GENERATING CIRCUIT 14 1 Oscillation circuit example 14 2 Clock...
Page 307: ...CLOCK GENERATING CIRCUIT 7751 Group User s Manual 14 6 14 2 Clock MEMORANDUM...
Page 360: ...CHAPTER 16 STANDARD CHARACTERISTICS 16 1 Standard characteristics...
Page 366: ...CHAPTER 17 APPLICATIONS 17 1 Memory expansion...
Page 405: ...APPLICATIONS 7751 Group User s Manual 17 40 17 1 Memory expansion MEMORANDUM...
Page 406: ...CHAPTER 18 PROM VERSION 18 1 EPROM mode 18 2 Usage precaution...
Page 417: ...7751 Group User s Manual PROM VERSION 18 12 18 2 Usage precaution MEMORANDUM...
Page 418: ...CHAPTER 19 FLASH MEMORY VERSION 19 1 Parallel input output mode 19 2 Serial input output mode...
Page 451: ...FLASH MEMORY VERSION 7751 Group User s Manual 19 34 19 2 Serial input output mode MEMORANDUM...
Page 484: ...APPENDIX 7751 Group User s Manual 20 33 Appendix 4 Package outlines 80D0...
Page 489: ...APPENDIX 7751 Group User s Manual 20 38 Appendix 6 Hexadecimal instruction code table...
Page 490: ...APPENDIX 7751 Group User s Manual 20 39 Appendix 6 Hexadecimal instruction code table...
Page 492: ...APPENDIX 7751 Group User s Manual 20 41 Appendix 7 Machine instructions...
Page 493: ...APPENDIX 7751 Group User s Manual 20 42 Appendix 7 Machine instructions...
Page 494: ...APPENDIX 7751 Group User s Manual 20 43 Appendix 7 Machine instructions...
Page 495: ...APPENDIX 7751 Group User s Manual 20 44 Appendix 7 Machine instructions...
Page 496: ...APPENDIX 7751 Group User s Manual 20 45 Appendix 7 Machine instructions...
Page 497: ...APPENDIX 7751 Group User s Manual 20 46 Appendix 7 Machine instructions...
Page 498: ...APPENDIX 7751 Group User s Manual 20 47 Appendix 7 Machine instructions...
Page 499: ...APPENDIX 7751 Group User s Manual 20 48 Appendix 7 Machine instructions...
Page 500: ...APPENDIX 7751 Group User s Manual 20 49 Appendix 7 Machine instructions...
Page 501: ...APPENDIX 7751 Group User s Manual 20 50 Appendix 7 Machine instructions...
Page 502: ...APPENDIX 7751 Group User s Manual 20 51 Appendix 7 Machine instructions...
Page 503: ...APPENDIX 7751 Group User s Manual 20 52 Appendix 7 Machine instructions...
Page 504: ...APPENDIX 7751 Group User s Manual 20 53 Appendix 7 Machine instructions...
Page 505: ...APPENDIX 7751 Group User s Manual 20 54 Appendix 7 Machine instructions...
Page 506: ...APPENDIX 7751 Group User s Manual 20 55 Appendix 7 Machine instructions...
Page 507: ...APPENDIX 7751 Group User s Manual 20 56 Appendix 7 Machine instructions...
Page 508: ...APPENDIX 7751 Group User s Manual 20 57 Appendix 7 Machine instructions...
Page 509: ...APPENDIX 7751 Group User s Manual 20 58 Appendix 7 Machine instructions...
Page 510: ...APPENDIX 7751 Group User s Manual 20 59 Appendix 7 Machine instructions...
Page 511: ...APPENDIX 7751 Group User s Manual 20 60 Appendix 7 Machine instructions...
Page 535: ...APPENDIX Appendix 9 Q A 7751 Group User s Manual 20 84 MEMORANDUM...
Page 536: ...GLOSSARY...
Page 539: ...GLOSSARY 7751 Group User s Manual 4 MEMORANDUM...