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Serial Communication Controllers (SCCs)
MC68360 USER’S MANUAL
exceeds the length of the data buffer, the BISYNC controller will fetch the next BD in the
table and, if it is empty, will continue to transfer data to this BD’s associated data buffer.
When a BCS is received, it is checked and written to the data buffer. The BISYNC controller
sets the last bit, writes the message status bits into the BD, and clears the E-bit. Then it gen-
erates a maskable interrupt, indicating that a block of data has been received and is in mem-
ory. Note that the SYNCs in the non-transparent mode or DLE-SYNC pairs in the
transparent mode (i.e., an underrun condition) are not included in the BCS calculations.
NOTE
The receive FIFO width (RFW) bit in the GSMR must be set for
an 8-bit receive FIFO for the BISYNC receiver.
7.10.20.4 BISYNC MEMORY MAP. When configured to operate in BISYNC mode, the
QUICC overlays the structure listed in Table 7-5 with the BISYNC-specific parameters
described in Table 7-9.
NOTE: Boldfaced items should be initialized by the user.
PRCRC and PTCRC. These value should be preset to all ones or all zeros, depending on
the BCS used.
PAREC. This 16-bit (modulo 216) counter is maintained by the CP. It may be initialized by
the user while the channel is disabled. The counter counts parity errors on receive if the par-
ity feature of BISYNC is enabled.
Table 7-9. BISYNC-Specific Parameters
Address
Name
Width
Description
SCC Base + 30
RES
Long
Reserved
SCC Base + 34
CRCC
Long
CRC Constant Temp Value
SCC Base + 38
PRCRC
Word
Preset Receiver CRC16/LRC
SCC Base + 3A
PTCRC
Word
Preset Transmitter CRC16/LRC
SCC Base + 3C
PAREC
Word
Receive Parity Error Counter
SCC Base + 3E
BSYNC
Word
BISYNC SYNC Character
SCC Base + 40
BDLE
Word
BISYNC DLE Character
SCC Base + 42
CHARACTER1
Word
CONTROL Character 1
SCC Base + 44
CHARACTER2
Word
CONTROL Character 2
SCC Base + 46
CHARACTER3
Word
CONTROL Character 3
SCC Base + 48
CHARACTER4
Word
CONTROL Character 4
SCC Base + 4A
CHARACTER5
Word
CONTROL Character 5
SCC Base + 4C
CHARACTER6
Word
CONTROL Character 6
SCC Base + 4E
CHARACTER7
Word
CONTROL Character 7
SCC Base + 50
CHARACTER8
Word
CONTROL Character 8
SCC Base + 52
RCCM
Word
Receive Control Character Mask
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