FUJITSU Semiconductor Controller MB89950/950A - Manual (Page 230)

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CHAPTER 10 UART
10.6 Operation of UART
This section describes the operation of the UART.
The UART has a serial communication function (operation mode 0,1,3).
■ Operation of UART
●
Operation mode
The UART has 3 operation modes. The mode 0, 1, 3 are standard serial transmission modes in which a data
type from 4-bit data length/parity to 9-bit data length/non-parity is selected (See Table 10.1-1 "UART
operating mode").
●
Transfer data format
The UART can handle data type of the NRZ (Non Return to Zero) system only.
The transmission data always begins with a start bit ("L" level) followed by a specified length of data bits
arranged in the "LSB first" format and ends with stop bit(s) ("H" level).
In asynchronous transfer mode, the relation between serial clock and serial input/output signal is not as
shown in Figure 10.6-1 "Transfer data format".
Figure 10.6-1 "Transfer data format" shows the relation between transmit/receive clock and data in
operation mode 1 when non-parity, 2 stop bits, synchronous transfer, transmit data of "01001101
B
" (8 bits)
are selected.
Figure 10.6-1 Transfer data format
Transmitting/receiving clock
Transmit/received data
0 1 0 1 1 0 0 1 0 1 1
START MSB STOP STOP LSB