MC68LC302 Datasheet, PDF (82/169 Pages) Motorola, Inc – Low Power Integrated Multiprotocol Processor Reference Manual

Communications Processor (CP)
M2 – Match Character2 (Bit 9)
When this bit is set, the character received matched the User Defined Character 2. The
received character is written into the receive control character register (RCCR).
M1 – Match Character1 (Bit 8)
When this bit is set, the character received matched the User Defined Character 1. The
received character is written into the receive control character register (RCCR).
EOT – End Of Table (bit 3)
When this bit is set, the autobaud controller measured start length exceeded the maxi-
mum start length of the last entry in the lookup table (lowest baud rate).
NOTE
The user must clear this bit when it is set.
OV – Overrun (bit 1)
If this bit is set, a receiver overrun occurred during autobaud reception.
NOTE
The user must clear this bit when it is set.
CD – Carrier Detect Lost (bit 0)
If this bit is set, the carrier detect signal was negated during autobaud reception.
NOTE
The user must clear this bit when it is set.
Lookup Table Size - Lookup table size is the number of baud rate entries in the external
lookup table.
Lookup Table Pointer - The lookup table pointer is the address in the external RAM where
the lookup table begins.
NOTE
The lookup table cannot cross a 64k memory block boundary.
4.3.9.4.4 Autobaud Lookup Table. The autobaud controller uses an external lookup table
to determine the baud rate while in the process of receiving a character. The lookup table
contains two entries for each supported baud rate. The first entry is the maximum start
length for the particular baud rate, and the second entry is the nominal length for a 1/2
START bit.
To determine the two values for each table entry, first calculate the autobaud sampling rate
(EQ 2). To do this EQ 1 must be used until EQ 2 is satisfied. The sampling rate is the lowest
speed baud rate that can be generated by the SCC baud rate generator that is over a thresh-
old defined in EQ 2.
BRG Clk Rate = System Clock or TIN1 / ((Clock Divider bits in SCON) + 1)
(EQ 1)
MOTOROLA
MC68LC302 REFERENCE MANUAL
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