Rohm LAPIS SEMICONDUCTOR ML620Q503, Руководство пользователя

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ML620Q503/Q504 User's Manual
Chapter 14 UART with FIFO(UARTF)
FEUL620Q504 14-4
14.2.2 UARTF0 Transmit/Receive Buffer (UAF0BUF)
Address: 0F7C0H
Access: R/W
Access size: 8/16 bits
Initial value: Undefined
7 6 5 4 3 2 1 0
UAF0BUFL UF0B7 UF0B6 UF0B5 UF0B4 UF0B3 UF0B2 UF0B1 UF0B0
R/W R/W R/W R/W R/W R/W R/W R/W R/W
Initial value x x x x x x x x
15 14 13 12 11 10 9 8
UAF0BUFH UF0B15 UF0B14 UF0B13 UF0B12 UF0B11 UF0B10 UF0B9 UF0B8
R/W R/W R/W R/W R/W R/W R/W R/W R/W
Initial value 0 0 0 0 0 0 0 0
UAF0BUF is a special function register (SFR) that provides the following three functions.
(1)
Read-only register for buffering received data: Receiver Buffer Register (RBR)
RBR is the register that holds received data from 5 to 8 bits depending on the character length.
The bit 0 of a data word is always the first serial data bit received. If data less than 8 bits is received, the data
is entered in the right justified manner towards the LSB.
When the UART carries out parallel-to-serial or serial-to-parallel conversion operation, the register has the
double buffer configuration so that read operations can be made.
RBR can be read by program when UF0DLAB of UAF0MOD is 0. When UAF0BUF is read, RBR can be
read from UnB7-0. For UF0B15-8, 00H can be read.
The reset value is undefined.
(2)
Write-only register for setting transmitted data: Transmitter Holding Register (THR)
THR is the register that holds transmitted data from 5 to 8 bits depending on the character length.
The bit 0 of the data word is always the first serial data bit that is transmitted.
When the UART carries out parallel-to-serial or serial-to-parallel conversion operation, the register has the
double buffer configuration so that write operations can be made.
THR can be written by program when UF0DLAB of UAF0MOD is 0. When UAF0BUF is written, the
UF0B7-0 data is written to THR. The UF0B15-8 data are invalid.
(3)
16-bit divisor latch for baud rate generator: Divisor Latch Resister (DLR)
DLR can be read/written by program when UF0DLAB of UAF0MOD is 1. For details, see "Baud rate clock
generation".
UF0DLAB = 0 UF0DLAB = 1
UAF0BUF[15:8] UAF0BUF[7:0] UAF0BUF[15:8] UAF0BUF[7:0]
Read 00H RBR DLR[15:8] DLR[7:0]
Write Disabled THR DLR[15:8] DLR[7:0]