MC68LC302 Datasheet, PDF (74/169 Pages) Motorola, Inc – Low Power Integrated Multiprotocol Processor Reference Manual

Communications Processor (CP)
the Chip Select address comparison, so they should be pro-
grammed to a value which will assert the desired chip select.
4.3.6 SCC Parameter RAM Memory Map
Each SCC maintains a section in the dual-port RAM called the parameter RAM. Each SCC
parameter RAM area begins at an offset $80 from each SCC base area ($400 or $500) and
continues through offset $BF. Part of each SCC parameter RAM (offset $80–$9A), which is
identical for each protocol chosen, is shown in Table 4-1. Offsets $9C–$BF comprise the
protocol-specific portion of the SCC parameter RAM. The SCC parameters have not
changed functionality from the MC68302.
Table 4-1. SCC Parameter RAM Memory Map
Address
SCC Base + 80 #
SCC Base + 81 #
SCC Base + 82 #
SCC Base + 84 ##
SCC Base + 86 ##
SCC Base + 87 ##
SCC Base + 88
SCC Base + 8C
SCC Base + 8E
SCC Base + 90 ##
SCC Base + 92 ##
SCC Base + 93 ##
SCC Base + 94
SCC Base + 98
SCC Base + 9A
SCC Base + 9C
SCC Base + BF
Name
RFCR
TFCR
MRBLR
RBD#
TBD#
Width
Byte
Byte
Word
Word
Byte
Byte
2 Words
Word
Word
Word
Byte
Byte
2 Words
Word
Word
Description
Rx Function Code
Tx Function Code
Maximum Rx Buffer Length
Rx Internal State
Reserved
Rx Internal Buffer Number
Rx Internal Data Pointer
Rx Internal Byte Count
Rx Temp
Tx Internal State
Reserved
Tx Internal Buffer Number
Tx Internal Data Pointer
Tx Internal Byte Count
Tx Temp
First Word of Protocol-Specific Area
Last Word of Protocol-Specific Area
# Should be initialized by the user (M68000 core).
## Modified by the CP following a CP or system reset.
4.3.7 Interrupt Mechanism
The interrupt mechanism for each SCC is the same as the MC68302.
4.3.8 UART Controller
The functionality of the UART controller has not changed. The new Autobaud feature is dis-
cussed in 4.3.9 Autobaud Controller (New). For any additional information on parameters,
registers, and functionality, please refer to the MC68302 Users’ Manual.
4.3.8.1 UART MEMORY MAP. When configured to operate in UART mode, the IMP over-
lays the structure (see Table 4-2) onto the protocol-specific area of that SCC's parameter
RAM. Refer to System Configuration Registers on page 5 for the placement of the three
SCC parameter RAM areas and to Table 4-1 for the other parameter RAM values
MOTOROLA
MC68LC302 REFERENCE MANUAL
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