Transmit End Flag - Philips CEM2100/00 Service Manual

xxxx
TD2BUF
***** 1
Shift register
TXD2 pin
UART2SR<TBEP>
INTTXD2 interrupt
Figure 13-9 Generation of Transmit Data Buffer Empty

13.9.6 Transmit End Flag

When data are transmitted and no data is in TD2BUF (UART2SR<TBEP> = "1"), transmit end flag
UART2SR<TEND> is set to "1". The UART2SR<TEND> is cleared to "0" when the data transmit is started
after writing the TD2BUF.
Shift register
TXD2 pin
UART2SR<TBEP>
UART2SR<TEND>
INTTXD2 interrupt
Figure 13-10 Generation of Transmit End Flag and Transmit Data Buffer Empty
Data write
yyyy
1xxxx0 * 1xxxx
Start Bit 0
1xx 1x ***** 1
****
***
Stop
Page 157
**** 1x ***** 1
Final bit Stop
Data write for TD2BUF
T5CL8
Data write
zzzz
1yyyy0
After reading UART2SR writing
TD2BUF clears TBEP.
* 1yyyy
1yyyy0
Bit 0
Start