SERIAL I/O
7751 Group User’s Manual
7–13
7.2.6 UARTi baud rate register (BRGi)
The UARTi baud rate register (BRGi) is an 8-bit timer exclusively used for UARTi to generate a transfer
clock. It has a reload register. Assuming that a value set in the BRGi is “n” (n = “00
16
” to “FF
16
”), the BRGi
divides the count source frequency by n + 1.
In the clock synchronous serial I/O mode, the BRGi is valid when an internal clock is selected, and a clock
of which frequency is the BRGi output’s frequency divided by 2 becomes the transfer clock. In the UART
mode, the BRGi is always valid, and a clock of which frequency is the BRGi output’s frequency divided by
16 becomes the transfer clock.
The data which is written to the addresses 31
16
and 39
16
is written to both the timer register and the reload
register whether transmission/reception is stopped or in progress. Accordingly, writing to their addresses,
perform it while that is stopped.
Figure 7.2.10 shows the structure of the UARTi baud rate register (BRGi); Figure 7.2.11 shows the block
diagram of transfer clock generating section.
7.2 Block description
Fig. 7.2.11 Block diagram of transfer clock generating section
BRGi
1/2
Transmit control circuit
Receive control circuit
Transfer clock for transmit operation
Transfer clock for receive operation
Transmit control circuit
Receive control circuit
Transfer clock for transmit operation
Transfer clock for receive operation
BRGi
1/16
<Clock synchronous serial I/O mode>
<UART mode>
f
i
: Clock selected by BRG count source select bits (f
2
/f
4
, f
16
/f
32
, f
64
/f
128
, or f
512
/f
1024
)
f
EXT
: Clock input to CLK
i
pin (external clock)
1/16
f
i
f
EXT
f
EXT
f
i
b7
b0
UART0 baud rate register (Address 31
16
)
UART1 baud rate register (Address 39
16
)
Functions
Bit
At reset
RW
7 to 0
Can be set to “00
16
” to “FF
16
.”
Assuming that the set value = n, BRGi
divides the count source frequency by n + 1.
Undefined
WO
Fig. 7.2.10 Structure of UARTi baud rate register (BRGi)
Содержание 7700 FAMILY
Страница 2: ...MITSUBISHI 16 BIT SINGLE CHIP MICROCOMPUTER 7700 FAMILY 7751 SERIES 7751 Group User s Manual...
Страница 11: ...Table of Contents viii 7751 Group User s Manual MEMORANDUM...
Страница 12: ...CHAPTER 1 DESCRIPTION 1 1 Performance overview 1 2 Pin configuration 1 3 Pin description 1 4 Block diagram...
Страница 48: ...CHAPTER 3 INPUT OUTPUT PINS 3 1 Programmable I O ports 3 2 I O pins of internal peripheral devices...
Страница 157: ...TIMER B 6 28 7751 Group User s Manual 6 5 Pulse period pulse width measurement mode MEMORANDUM...
Страница 245: ...7751 Group User s Manual 8 36 A D CONVERTER Precautions when using A D converter MEMORANDUM...
Страница 246: ...CHAPTER 9 WATCHDOG TIMER 9 1 Block description 9 2 Operation description 9 3 Precautions when using watchdog timer...
Страница 254: ...CHAPTER 10 STOP MODE 10 1 Clock generating circuit 10 2 Operation description 10 3 Precautions for Stop mode...
Страница 260: ...CHAPTER 11 WAIT MODE 11 1 Clock generating circuit 11 2 Operation description 11 3 Precautions for Wait mode...
Страница 265: ...7751 Group User s Manual WAIT MODE 11 6 11 3 Precautions for Wait mode MEMORANDUM...
Страница 289: ...CONNECTION WITH EXTERNAL DEVICES 12 4 Hold function 7751 Group User s Manual 12 24 MEMORANDUM...
Страница 290: ...CHAPTER 13 RESET 13 1 Hardware reset 13 2 Software reset...
Страница 302: ...CHAPTER 14 CLOCK GENERATING CIRCUIT 14 1 Oscillation circuit example 14 2 Clock...
Страница 307: ...CLOCK GENERATING CIRCUIT 7751 Group User s Manual 14 6 14 2 Clock MEMORANDUM...
Страница 359: ...ELECTRICAL CHARACTERISTICS 7751 Group User s Manual 15 52 MEMORANDUM 15 15 Testing circuit for ports P0 to P8 1 and E...
Страница 360: ...CHAPTER 16 STANDARD CHARACTERISTICS 16 1 Standard characteristics...
Страница 365: ...STANDARD CHARACTERISTICS 16 1 Standard characteristics 7751 Group User s Manual 16 6 MEMORANDUM...
Страница 366: ...CHAPTER 17 APPLICATIONS 17 1 Memory expansion...
Страница 405: ...APPLICATIONS 7751 Group User s Manual 17 40 17 1 Memory expansion MEMORANDUM...
Страница 406: ...CHAPTER 18 PROM VERSION 18 1 EPROM mode 18 2 Usage precaution...
Страница 417: ...7751 Group User s Manual PROM VERSION 18 12 18 2 Usage precaution MEMORANDUM...
Страница 418: ...CHAPTER 19 FLASH MEMORY VERSION 19 1 Parallel input output mode 19 2 Serial input output mode...
Страница 451: ...FLASH MEMORY VERSION 7751 Group User s Manual 19 34 19 2 Serial input output mode MEMORANDUM...
Страница 483: ...APPENDIX 7751 Group User s Manual 20 32 Appendix 4 Package outlines Appendix 4 Package outlines 80P6N A...
Страница 484: ...APPENDIX 7751 Group User s Manual 20 33 Appendix 4 Package outlines 80D0...
Страница 489: ...APPENDIX 7751 Group User s Manual 20 38 Appendix 6 Hexadecimal instruction code table...
Страница 490: ...APPENDIX 7751 Group User s Manual 20 39 Appendix 6 Hexadecimal instruction code table...
Страница 491: ...APPENDIX 7751 Group User s Manual 20 40 Appendix 7 Machine instructions Appendix 7 Machine instructions...
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Страница 536: ...GLOSSARY...
Страница 539: ...GLOSSARY 7751 Group User s Manual 4 MEMORANDUM...