Notes On Serial I/O Port - Toshiba TMPR4937 Manual

23.5 Notes on Serial I/O Port

•
Restrictions on use of the break function in SIO
[Restriction]
To transmit breaks to TX4937, synchronize breaks to the start bit. Set consecutively the transmit data
to Low immediately after the start bit.
[Violation]
When the transmitting end transmits breaks to TX4937 in the middle of a transmission, TX4937
detects the first flame error only, but not breaks.
When the break reception is synchronized to the start bit (the receive data is consecutively set to Low
immediately after the start bit), breaks can be detected correctly.
(Malfunction)
Status
SIN
* Since the start bit is not recognized after a flame error, the receiving status is stopped in idle state.
(Correct operation)
Status
SIN
* When the receiving data is consecutively set to Low immediately after the start bit is recognized,
breaks can be detected.
When breaks are transmitted to TX4937, it may not receive breaks.
This malfunction may occur when the transmitting end transmits breaks to TX4937 in the middle of a
transmission.
[Workarounds]
To transmit breaks to TX4937, synchronize breaks to the start bit (set the transmitting data
consecutively to Low immediately after the start bit).
Chapter 23 Notes on Use of TMPR4937
S 1 2 3 4 5 6 7 8 P S
↑ ↑
Start Flame Error
S 1 2 3 4 5 6 7 8 P S S 1 2 3 4 5 6 7 8 P S
↑ ↑
st
Start 1 Break
23-10
↑
nd
2 Break