MC68LC302 Datasheet, PDF (90/169 Pages) Motorola, Inc – Low Power Integrated Multiprotocol Processor Reference Manual

Communications Processor (CP)
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
OFFSET + 0 R
X
W
I
L TB B BR TD TR — — — — UN CT
OFFSET + 2
DATA LENGTH
OFFSET + 4
OFFSET +6
TX BUFFER POINTER (24-bits used, upper 8 bits must be 0)
Figure 4-7. BISYNC Transmit Buffer Descriptor
4.3.11.5 BISYNC EVENT REGISTER. The SCC event register (SCCE) is referred to as the
BISYNC event register when the SCC is programmed as a BISYNC controller. It is an 8-bit
register used to report events recognized by the BISYNC channel and to generate inter-
rupts. On recognition of an event, the BISYNC controller sets the corresponding bit in the
BISYNC event register. Interrupts generated by this register may be masked in the BISYNC
mask register. A bit is cleared by writing a one. More than one bit may be cleared at a time.
All unmasked bits must be cleared before the CP will negate the internal interrupt request
signal. This register is cleared at reset.
7
6
5
4
3
2
1
0
CTS CD — TXE RCH BSY TX RX
4.3.11.6 BISYNC MASK REGISTER. The SCC mask register (SCCM) is referred to as the
BISYNC mask register when the SCC is operating as a BISYNC controller. It is an 8-bit read-
write register that has the same bit format as the BISYNC event register. If a bit in the
BISYNC mask register is a one, the corresponding interrupt in the event register will be
enabled. If the bit is zero, the corresponding interrupt in the event register will be masked.
This register is cleared upon reset.
4.3.12 Transparent Controller
The functionality of the BISYNC controller has not changed. For any additional information
on parameters, registers, and functionality, please refer to the MC68302 Users’ Manual.
4.3.12.1 TRANSPARENT MEMORY MAP. When configured to operate in transparent
mode, the IMP overlays the structure illustrated in Table 4-11 onto the protocol specific area
of that SCC parameter RAM. Refer to Table 2-6 for the placement of the three SCC param-
eter RAM areas and Table 4-1 for the other parameter RAM values.
MOTOROLA
MC68LC302 REFERENCE MANUAL
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