Status Flag; Parity Error; Framing Error; Overrun Error - Philips CEM2100/00 Service Manual

12.9 Status Flag

12.9.1 Parity Error

When parity determined using the receive data bits differs from the received parity bit, the parity error flag
UART1SR<PERR> is set to "1". The UART1SR<PERR> is cleared to "0" when the RD1BUF is read after
reading the UART1SR.
RXD1 pin
Shift register
UART1SR<PERR>
INTRXD1 interrupt

12.9.2 Framing Error

When "0" is sampled as the stop bit in the receive data, framing error flag UART1SR<FERR> is set to "1".
The UART1SR<FERR> is cleared to "0" when the RD1BUF is read after reading the UART1SR.
RXD1 pin
Shift register
UART1SR<FERR>
INTRXD1 interrupt

12.9.3 Overrun Error

When all bits in the next data are received while unread data are still in RD1BUF, overrun error flag
UART1SR<OERR> is set to "1". In this case, the receive data is discarded; data in RD1BUF are not affected.
The UART1SR<OERR> is cleared to "0" when the RD1BUF is read after reading the UART1SR.
Parity
xxxx0 **
Figure 12-5 Generation of Parity Error
Final bit
xxx0 **
Figure 12-6 Generation of Framing Error
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Stop
pxxxx0 1pxxxx0
*
After reading UART1SR then
RD1BUF clears PERR.
Stop
xxxx0
0xxxx0
*
After reading UART1SR then
RD1BUF clears FERR.
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