Operation Of Uart - Fujitsu MB90460 Series Hardware Manual

CHAPTER 17 UART
17.7

Operation of UART

UART operates in operation modes 0 and 2 for normal bidirectional serial
communication and in operation mode 1 for master-slave communication.
■ Operation of UART
●
Operation modes
There are three UART operation modes: modes 0 to 2. As listed in Table 17.7-1, an operation mode can be
selected according to the inter-CPU connection method and data transfer mode
Table 17.7-1 UART Operation Mode
Operation mode
When parity is disabled When parity is enabled
0 Normal mode
1 Multiprocessor
2 Normal mode
-: Setting not possible.
*1: "+1" indicates the address/data selection bit (A/D) for communication control.
*2: During reception, only one stop bit can be detected.
Note:
Operation mode 1 of UART is used only from the master system during master-slave connection.
●
Inter-CPU connection method
One-to-one connection (normal mode) and master-slave connection (multiprocessor mode) can be selected.
For either connection method, the data length, whether to enable parity, and the synchronization method
must be common to all CPUs. Select an operation mode as follows:
• In the one-to-one connection method, operation mode 0 or 2 must be used in the two CPUs. Select
operation mode 0 for asynchronous transfer mode and operation mode 2 for synchronous transfer mode.
• Select operation mode 1 for the master-slave connection method and use it from the master system.
Select "When parity is disabled" for this connection method.
●
Synchronization method
Asynchronous mode (start-stop synchronization) or clock synchronous mode can be selected in different
operation modes.
●
Signal mode
UART can treat data only in NRZ (Non-return to Zero) format.
498
Data length
7 or 8 bits
8+1*1 bits
8 bits
Synchronization mode Stop bit length
Asynchronous
– Asynchronous
– Synchronous
1 or 2 bits *2
None