Silicon Laboratories C8051F340 Instrukcja Użytkownika Pobierz pdf (Strona 226)

C8051F340/1/2/3/4/5/6/7

226 Rev. 0.5

SFR Definition 19.3. SBUF1: UART1 Data Buffer

SFR Definition 19.4. SBCON1: UART1 Baud Rate Generator Control

Bits7–0: SBUF1[7:0]: Serial Data Buffer Bits 7–0 (MSB-LSB)

This SFR is used to both send data from the UART and to read received data from the

UART1 receive FIFO.

Write: Writing a byte to SBUF1 initiates the transmission. When data is written to SBUF1, it

first goes to the Transmit Holding Register, where it is held for serial transmission. When the

transmit shift register is available, data is transferred into the shift register, and SBUF1 may

be written again.

Read: Reading SBUF1 retrieves data from the receive FIFO. When read, the oldest byte in

the receive FIFO is returned, and removed from the FIFO. Up to three bytes may be held in

the FIFO. If there are additional bytes available in the FIFO, the RI1 bit will remain at logic

‘1’, even after being cleared by software.

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

SFR Address:

0xD3

Bit7: RESERVED: Read = 0b; Must write 0b.

Bit6: SB1RUN: Baud Rate Generator Enable.

0: Baud Rate Generator is disabled. UART1 will not function.

1: Baud Rate Generator is enabled.

Bits5–2: RESERVED: Read = 0000b; Must write 0000b.

Bits1–0: SB1PS[1:0]: Baud Rate Prescaler Select.

00: Prescaler = 12

01: Prescaler = 4

10: Prescaler = 48

11: Prescaler = 1

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

Reserved SB1RUN Reserved Reserved Reserved Reserved SB1PS1 SB1PS0 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

Bit

Addressable

SFR Address:

0xAC

1 2 ... 221 222 223 224 225 226 227 228 229 230 231 ... 281 282

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Silicon Laboratories C8051F340 Instrukcja Użytkownika Strona 226