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CHAPTER 18 UART
18.7 Explanation of Operation of UART
18.7
Explanation of Operation of UART
UART supports the master/slave connection based communication function (operation
mode 1) as well as the typical bidirectional serial communication function (operation
mode 0, operation mode 2).
■ Operation of UART
●
Operating mode
UART has 3 types of operation modes (i.e. mode 0, 1, 2), which can be selected based on the appropriate
connection system or data transfer system between CPUs as shown in Table 18.7-1.
Table 18.7-1 UART Operation Modes
Operating mode
0
1
2
-: Unavailable
*1: "+1" indicates the address/data select bit (A/D) used for communication control.
*2: Only one bit can be detected as a stop bit at reception.
Note:
The UART operation mode 1 is used only for the master connection on the master/slave connection.
●
Inter-CPU connection method
Two alternatives are provided; one-to-one connection and master/slave connection. In both cases, the data
length, parity, synchronous mode, must be the same for all CPUs. The operation modes are selected as
follows.
One-to-one connection: 2 CPUs should adopt the same method either in the mode 0 or in the mode 2.
Master/slave connection: Set the operation mode 1. When selecting the operation mode 1, use this as
414
Without
Normal mode
Multiprocessor mode
8+1
Normal mode
Select the mode 0 in the asynchronous method and the mode 2 in the synchronous
method.
master. For this connection, select no parity and a data length of 8 bits.
FUJITSU MICROELECTRONICS LIMITED
Data length
With
Parity
Parity
7 bits or 8 bits
*1
-
bit
8 bits
-
MB90335 Series
Synchronous
Length of Stop Bit
type
Asynchronous
Asynchronous
Synchronous
CM44-10137-6E
1 bit
or
*2
2 bits
None
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