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Chapter 32 USART (LIN / FIFO)
4.USART Registers
4.4 Reception and Transmission Data Register (RDR04 / TDR04)
The reception data register (RDR04) holds the received data. The transmission data register (TDR04) holds
the transmission data. Both RDR04 and TDR04 registers are located at the same address.
(Note)
TDR04 is a write-only register and RDR04 is a read-only register. These registers are located in the
same address, so the read value is different from the write value. Therefore, instructions that perform
a read-modify-write (RMW) operation, such as the INC/DEC instruction, cannot be used.
Figure 4-4 Transmission and Reception Data registers 04 (RDR04 / TDR04)
■
Reception:
RDR04 is the register that contains reception data. The serial data signal transmitted to the SIN04 pin is
converted in the shift register and stored there. When the data length is 7 bits, the uppermost bit (D7) contains
0. When reception is complete the data is stored in this register and the reception data full flag bit (SSR04:
RDRF) is set to 1. If a reception interrupt request is enabled at this point, a reception interrupt occurs.
Read RDR04 when the RDRF bit of the status register (SSR04) is 1. The RDRF bit is cleared automatically to
0 when RDR04 is read. Also the reception interrupt is cleared if it is enabled and no error has occurred.
Data in RDR04 is invalid when a reception error occurs (SSR04: PE, ORE, or FRE = 1).
■
Transmission:
When data to be transmitted is written to the transmission data register in transmission enable state, it is
transferred to the transmission shift register, then converted to serial data, and transmitted from the serial data
output terminal (SOT04 pin). If the data length is 7 bits, the uppermost bit (D7) is not sent.
When transmission data is written to this register, the transmission data empty flag bit (SSR04: TDRE) is
cleared to 0. When transfer to the transmission shift register is complete, the bit is set to 1. When the TDRE bit
is 1, the next part of transmission data can be written. If output transmission interrupt requests have been
bit8
TIE: Transmission
interrupt request
enable bit
•
This bit enables or disables output of a request for transmission interrupt
to the CPU.
•
A transmission interrupt request is output when this bit and the TDRE bit
are 1.
Table 4-5 Functions of each bit of status register 04 (SSR04)
Bit name
Function
Initial value
0 0 0 0 0 0 0 0
B
R/W R/W R/W R/W
R/W
R/W
R/W R/W
bit8-0
R/W
Data Registers
Read
Read from Reception Data Register
Write
Write to Transmission Data Register
R/W
:
Readable and writable
7
6
5
4
3
2
1
0
Summary of Contents for FR Family FR60 Lite
Page 2: ...FUJITSU LIMITED ...
Page 3: ...FR60 32 BIT MICROCONTROLLER MB91460 Series User s Manual ...
Page 15: ...xi ...
Page 16: ...xii ...
Page 38: ...22 Chapter 2 MB91460 Rev A Rev B Overview 4 Block Diagram ...
Page 128: ...112 Chapter 4 CPU Architecture 9 Addressing ...
Page 153: ...137 Chapter 8 Device State Transition 3 State Transition Diagram ...
Page 154: ...138 Chapter 8 Device State Transition 3 State Transition Diagram ...
Page 169: ...153 Chapter 9 Reset 10 Caution ...
Page 170: ...154 Chapter 9 Reset 10 Caution ...
Page 180: ...164 Chapter 10 Standby 7 Q A ...
Page 182: ...166 Chapter 10 Standby 8 Caution ...
Page 199: ...183 Chapter 12 Instruction Cache 2 Main body structure Figure 2 3 I Cache Address Map ...
Page 200: ...184 Chapter 12 Instruction Cache 2 Main body structure Figure 2 4 I Cacheable Area ...
Page 222: ...206 Chapter 13 Clock Control 8 Caution ...
Page 232: ...216 Chapter 14 PLL Interface 7 Caution ...
Page 236: ...220 Chapter 15 CAN Clock Prescaler 3 Registers ...
Page 288: ...272 Chapter 19 Timebase Timer 8 Caution ...
Page 314: ...298 Chapter 22 Main Oscillation Stabilisation Timer 8 Caution ...
Page 326: ...310 Chapter 23 Sub Oscillation Stabilisation Timer 8 Caution ...
Page 348: ...332 Chapter 25 External Interrupt 8 Caution ...
Page 398: ...382 Chapter 26 DMA Controller 6 DMA External Interface ...
Page 402: ...386 Chapter 27 Delayed Interrupt 8 Caution ...
Page 412: ...396 Chapter 28 Bit Search 8 Caution ...
Page 521: ...505 Chapter 30 I O Ports 3 Port Register Settings ...
Page 522: ...506 Chapter 30 I O Ports 3 Port Register Settings ...
Page 574: ...558 Chapter 31 External Bus 4 Endian and Bus Access Byte Access ...
Page 628: ...612 Chapter 31 External Bus 13 Notes on Using the External Bus Interface ...
Page 706: ...690 Chapter 33 I2C Controller 4 Programming Flow Charts ...
Page 748: ...732 Chapter 34 CAN Controller 4 CAN Application ...
Page 762: ...746 Chapter 35 Free Run Timer 8 Caution ...
Page 790: ...774 Chapter 37 Output Compare 8 Caution ...
Page 838: ...822 Chapter 39 Programmable Pulse Generator 8 Caution ...
Page 850: ...834 Chapter 40 Pulse Frequency Modulator 4 PFM Operation and Setting ...
Page 886: ...870 Chapter 42 Sound Generator 3 Registers ...
Page 900: ...884 Chapter 43 Stepper Motor Controller 4 Caution ...
Page 939: ...923 Chapter 47 LCD Controller 3 Configuration Figure 3 2 Register List ...
Page 943: ...927 Chapter 47 LCD Controller 4 Registers Correspondence between VRAM and Common Segment Pins ...
Page 964: ...948 Chapter 48 Clock Monitor 8 Caution ...
Page 994: ...978 Chapter 51 Low Voltage Reset Interrupt 3 Registers ...
Page 998: ...982 Chapter 52 Regulator Control 3 Registers ...
Page 1008: ...992 Chapter 53 Fixed Mode Reset Vector BOOT ROM 5 Bootloader Update Strategy ...
Page 1024: ...1008 Chapter 54 Flash Memory 8 Caution ...
Page 1032: ...1016 Chapter 55 Flash Security 4 Register ...
Page 1034: ...1018 Chapter 56 Electrical Specification ...
Page 1035: ...FR60 MB91460 Series Hardware Manual European Microcontroller Design Centre Author MBo ...
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