tmp88cs43fg TOSHIBA Semiconductor CORPORATION, tmp88cs43fg Datasheet - Page 182

• Manufacturer Part Number: tmp88cs43fg
• Description: 8 Bit Microcontroller Tlcs-870/x Series
• Manufacturer: TOSHIBA Semiconductor CORPORATION

14. Asynchronous Serial interface (UART)
14.9 Status Flag
14.9.4 Receive Data Buffer Full
14.9.5 Transmit Data Buffer Empty
RXD pin
RDBUF
UARTSR<RBFL>
INTRXD interrupt
Shift register
UARTSR<RBFL> is cleared to “0” when the RDBUF is read after reading the UARTSR.
shift register and data transmit starts, transmit data buffer empty flag UARTSR<TBEP> is set to “1”. The
UARTSR<TBEP> is cleared to “0” when the TDBUF is written after reading the UARTSR.
UARTSR<RBFL>
RXD pin
RDBUF
UARTSR<OERR>
INTRXD interrupt
Shift register
Note:Receive operations are disabled until the overrun error flag UARTSR<OERR> is cleared.
Loading the received data in RDBUF sets receive data buffer full flag UARTSR<RBFL> to "1". The
Note:If the overrun error flag UARTSR<OERR> is set during the period between reading the UARTSR and reading
When no data is in the transmit buffer TDBUF, that is, when data in TDBUF are transferred to the transmit
the RDBUF, it cannot be cleared by only reading the RDBUF. Therefore, after reading the RDBUF, read the
UARTSR again to check whether or not the overrun error flag which should have been cleared still remains
set.
Figure 14-8 Generation of Receive Data Buffer Full
Figure 14-7 Generation of Overrun Error
xxx0 **
yyyy
xxx0 **
yyyy
Final bit
Final bit
Page 172
xxxx0
xxxx0
*
*
Stop
Stop
1xxxx0
xxxx
1xxxx0
After reading UARTSR then
RDBUF clears RBFL.
After reading UARTSR then
RDBUF clears OERR.
TMP88CS43FG