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Serial Communication Controllers (SCCs)
MC68360 USER’S MANUAL
NOTE: The items in boldface should be initialized by the user.
7.10.7.1 BD TABLE POINTER (RBASE, TBASE). The RBASE and TBASE entries define
the starting location in the dual-port RAM for the set of BDs for receive and transmit func-
tions of the SCC. This provides a great deal of flexibility in how BDs for an SCC are parti-
tioned. By selecting RBASE and TBASE entries for all SCCs, and by setting the W-bit in the
last BD in each BD list, the user may select how many BDs to allocate for the transmit and
receive side of every SCC. The user must initialize these entries before enabling the corre-
sponding channel. Furthermore, the user should not configure BD tables of two enabled
SCCs to overlap, or erratic operation will occur.
NOTE
RBASE and TBASE should contain a value that is divisible by 8.
7.10.7.2 SCC FUNCTION CODE REGISTERS (RFCR, TFCR). There are eight separate
function code registers for the four SCC channels: four for receive data buffers (RFCRx) and
four for transmit data buffers (TFCRx). The FC entry contains the value that the user would
like to appear on the function code pins FC3–FC0 when the associated SDMA channel
accesses memory. It also controls the byte-ordering convention to be used in the transfers.
Receive Function Code Register
Table 7-5. SCC Parameter RAM Common to All Protocols
Address
Name
Width
Description
SCC Base + 00
RBASE
Word
Rx BD Base Address
SCC Base + 02
TBASE
Word
Tx BD Base Address
SCC Base + 04
RFCR
Byte
Rx Function Code
SCC Base + 05
TFCR
Byte
Tx Function Code
SCC Base + 06
MRBLR
Word
Maximum Receive Buffer Length
SCC Base + 08
RSTATE
Long
Rx Internal State
SCC Base + 0C
Long
Rx Internal Data Pointer
SCC Base + 10
RBPTR
Word
Rx BD Pointer
SCC Base + 12
Word
Rx Internal Byte Count
SCC Base + 14
Long
Rx Temp
SCC Base + 18
TSTATE
Long
Tx Internal State
SCC Base + 1C
Long
Tx Internal Data Pointer
SCC Base + 20
TBPTR
Word
Tx BD Pointer
SCC Base + 22
Word
Tx Internal Byte Count
SCC Base + 24
Long
Tx Temp
SCC Base + 28
RCRC
Long
Temp Receive CRC
SCC Base + 2C
TCRC
Long
Temp Transmit CRC
SCC Base + 30
First Word of Protocol-Specific Area
SCC Base + xx
Last Word of Protocol-Specific Area
76543210
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MOT
FC3–FC0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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