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CHAPTER 9 I/O PORT
9.9.2
Operations of Port B
This section describes the operations of port B.
■
Operations of Port B
●
Operation as an output port
•
Setting the corresponding DDR bit to "1" sets a pin as an output port.
•
For a peripheral function sharing pins, disable its output.
•
When a pin is set as an output port, it outputs the value of the PDR to pins.
•
If data is written to the PDR, the value is stored in the output latch and output to the pin as it is.
•
Reading the PDR returns the PDR value.
●
Operation as an input port
•
Setting the corresponding DDR bit to "0" sets a pin as an input port.
•
For a peripheral function sharing pins, disable its output.
•
When using the LCD shared pin as an input port, set the port input control bits (PICTL) in the LCDC
enable register (LCDCE1) to "1".
•
If data is written to the PDR, the value is stored in the output latch but not output to the pin.
•
Reading the PDR returns the pin value. However, the read-modify-write command returns the PDR
value.
●
Operation at reset
•
When the CPU is reset, the values of the DDR register and PICT bit of the LCDCE1 register are
initialized to "0", and port input becomes disabled.
●
Operation in stop mode and watch mode
•
After moving to stop mode or watch mode, setting the standby control register pin state specification bit
(STBC:SPL) to "1" forces the pin into high impedance, regardless of the value of the DDR register.Note
that input is locked to "L" and blocked, in order to prevent leaks from freed input. If, however,peripheral
function input is enabled for the interrupt pin selection circuit (EC0), input is enabled and not blocked.
•
If the pin state specification bit is "0", the state remains in port I/O or peripheral function I/O, and the
output level is maintained.
●
Behavior during peripheral function output
•
Setting the output enable bit of a peripheral function sets the corresponding pin as a peripheral function
output.
•
The pin value can be read from the PDR register even if the peripheral function output is enabled.
Therefore, the output value of a peripheral function can be read by the read operation on PDR register.
However, the read-modify-write command returns the PDR value.
●
Behavior during peripheral function input
•
Set the DDR register bit corresponding to the peripheral function input pin to "0" to change to an input
port.
Summary of Contents for F2 MC-8FX Family
Page 2: ......
Page 4: ......
Page 34: ...20 CHAPTER 1 DESCRIPTION ...
Page 38: ...24 CHAPTER 2 HANDLING DEVICES ...
Page 39: ...25 CHAPTER 3 MEMORY SPACE This chapter describes memory space 3 1 Memory Space 3 2 Memory Map ...
Page 56: ...42 CHAPTER 5 CPU ...
Page 73: ...59 CHAPTER 6 CLOCK CONTROLLER ...
Page 96: ...82 CHAPTER 6 CLOCK CONTROLLER ...
Page 104: ...90 CHAPTER 7 RESET ...
Page 105: ...91 CHAPTER 8 INTERRUPTS This chapter explains the interrupts 8 1 Interrupts ...
Page 174: ...160 CHAPTER 10 TIMEBASE TIMER ...
Page 184: ...170 CHAPTER 10 TIMEBASE TIMER ...
Page 218: ...204 CHAPTER 13 WATCH PRESCALER ...
Page 257: ...243 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 261: ...247 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 288: ...274 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 301: ...287 CHAPTER 17 16 BIT PPG TIMER ...
Page 316: ...302 CHAPTER 17 16 BIT PPG TIMER ...
Page 382: ...368 CHAPTER 21 UART SIO DEDICATED BAUD RATE GENERATOR ...
Page 390: ...376 CHAPTER 22 I2C ...
Page 395: ...381 CHAPTER 22 I2C ...
Page 399: ...385 CHAPTER 22 I2C ...
Page 430: ...416 CHAPTER 23 10 BIT A D CONVERTER ...
Page 476: ...462 CHAPTER 24 LCD CONTROLLER ...
Page 482: ...468 CHAPTER 25 LOW VOLTAGE DETECTION RESET CIRCUIT ...
Page 494: ...480 CHAPTER 26 CLOCK SUPERVISOR ...
Page 507: ...493 CHAPTER 27 REAL TIME CLOCK ...
Page 523: ...509 CHAPTER 27 REAL TIME CLOCK ...
Page 532: ...518 CHAPTER 27 REAL TIME CLOCK ...
Page 536: ...522 CHAPTER 28 256 KBIT FLASH MEMORY ...
Page 554: ...540 CHAPTER 28 256 KBIT FLASH MEMORY ...
Page 564: ...550 CHAPTER 29 EXAMPLE OF SERIAL PROGRAMMING CONNECTION ...
Page 595: ...581 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 596: ...582 INDEX Index ...
Page 597: ...583 INDEX ...
Page 600: ...586 Pin Function Index ...
Page 602: ......