Freescale Semiconductor PowerQUICC MPC885 Reference Manual page 680

SCC UART Mode
If the received control character is not rejected, it is written to the receive buffer. The receive buffer is then
automatically closed to allow software to handle end-of-message characters. Control characters that are
not part of the actual message, such as XOFF, can be rejected. Rejected characters bypass the receive
buffer and are written directly to the received control character register (RCCR), which triggers maskable
interrupt.
The 16-bit entries in the control character table support control character recognition. Each entry consists
of the control character, a valid bit (end of table), and a reject bit. See
1
Offset
0 1
0x50 E R
0x52 E R
• • •
• • •
• • •
0x5E E R
0x60 1 1
0x62
1
From SCC x base address
Table 22-4 describes the data structure used in control character recognition
Table 22-4. Control Character Table, RCCM, and RCCR Descriptions
Offset Bits Name
0x50– 0
0x5E
1
2–7
CHARACTER n Control character values 1–8. Defines control characters to be compared to the
8–15
22-8
2
—
—
•
•
•
—
—
—
Figure 22-3. Control Character Table, RCCM, and RCCR
E End of table. In tables with eight control characters, E is always 0.
0 This entry is valid.
1 The entry is not valid and is not used.
R Reject character.
0 A matching character is not rejected but is written into the Rx buffer, which is
then closed. If RxBD[I] is set, the buffer closing generates a maskable interrupt
through SCCE[RX]. A new buffer is opened if more data is in the message.
1 A matching character is written to RCCR and not to the Rx buffer. A maskable
interrupt is generated through SCCE[CCR]. The current Rx buffer is not closed.
— Reserved
incoming character. For characters smaller than 8 bits, the most significant bits
should be zero.
MPC885 PowerQUICC Family Reference Manual, Rev. 2
Figure 22-3.
7 8
CHARACTER1
CHARACTER2
CHARACTER8
RCCM
RCCR
Description
15
•
•
•
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