PEB20534H-10V2.1 Infineon Technologies, PEB20534H-10V2.1 Datasheet - Page 194

• Manufacturer Part Number: PEB20534H-10V2.1
• Description: Communication Controller 208-Pin FQFP
• Manufacturer: Infineon Technologies

– if it is correctly framed (correct length),
– if its bits match the ones in the XON or XOFF registers over the programmed character
– if it has correct parity (if applicable).
Received XON and XOFF characters are stored in the SCC receive FIFO, as any other
characters, when bit DXS is set to ’0’ in register CCR2. Otherwise they are not stored in
the receive FIFO.
In-Band Flow Control of Transmitted Characters:
Recognition of an XON or XOFF character causes always a corresponding maskable
interrupt status to be generated.
Further action depends on the setting of control bit ’FLON’ (Flow Control On) in register
CCR2:
0: No further action is automatically taken by the SCC.
1: The reception of an XOFF character automatically turns off the transmitter after the
After hardware RESET, bit CCR2:FLON is ‘0’.
When bit CCR2:FLON is programmed from ‘0’ to ‘1’, the transmitter is first in the
‘XON state’, until an XOFF character is received.
When bit CCR2:FLON is programmed from ‘1’ to ‘0’, the transmitter always goes in the
‘XON state’, and transmission is only controlled by the user and by the CTS signal input.
The in-band flow control of the transmitter via received XON and XOFF characters can
be combined with control via CTS pin, i.e. the effect of the CTS pin is independent of
whether in-band control is used or not. The transmitter is enabled only if CTS is ‘low’ and
XON state has been reached.
Transmitter Status Bit:
The status bit ‘Flow Control Status’ (bit ’FCS’ in register STAR) indicates the current
state of the transmitter, as follows:
0: if the transmitter is in XON state,
1: if the transmitter is in XOFF state.
Note: The transmitter cannot be turned off by software without disrupting data possibly
Flow Control for Received Data:
After writing a character value to register TICR (Transmit Immediate Character) its
character contents is inserted into the outgoing character stream
• immediately upon writing this register by the microprocessor if the transmitter is in
Data Sheet
length,
currently transmitted character (if any) has been shifted out completely (entering
XOFF state). The reception of an XON character automatically makes the transmitter
resume transmitting (entering XON state).
IDLE state. If no further characters (transmit FIFO empty) are to be transmitted, i.e.
remaining in the transmit FIFO.
194
Detailed Protocol Description
PEB 20534
PEF 20534
2000-05-30