The serial interface of the H8 family and the H8S family is divided into a transmit part and a receive part structurally to be used for both asynchronous and functions.
The transmit part and the receive part can be operated individually. When in synchronous transmit/receive data, each part is synchronized and operated.
At the same time, the TE bit and the RE bit play a role in clock source supply gate for each transmitter part and receive part.
When the TE and the RE were set separately, the clock source for the transmit part and the receive part will not work together. As a result, the TE and the RE would not be operated at once.
Therefore please set the TE and the RE to “1” all at once when in transmit/receive operation.
Also, the same rule applies in the operation mode change from transmit mode (TE=1, RE=0) and receive mode (TE=0, RE=1) to transmit/receive mode (TE=1, RE=1).
In such a mode change case, after setting the serial interface to TE=0 and RE=0, set TE and RE to “1” all at once.
(Note: when the serial interface is set to TE=0 and RE=0, the TxD and RxD pins will be switched to each general port.)
Regardless of a half duplex or full duplex, we recommend you to use transmit/receive mode (TE=1, RE=1) preliminary when in both of transmit and receive operations.
|H8S/2630, 2639, 2638, 2636, 2635|
|H8S/2556, 2552, 2506|
|H8S/2258, 2239, 2238, 2237, 2227|