TC1796
System Units (Vol. 1 of 2)
LMB External Bus Unit
User’s Manual 13-103 V2.0, 2007-07
EBU, V2.0
Field Bits Type Description
MULTMAP [6:0] rw Multiplier Map
This bit field is a mask value that determines whether
or not a specific bus access parameter as defined in
register EMUBAP is multiplied by the value of bit field
CMULT.
XXXXXX0
B
ADDRC is not multiplied.
XXXXXX1
B
ADDRC is multiplied by CMULT.
XXXXX0X
B
Reserved, don’t care.
XXXXX1X
B
Reserved, don’t care.
XXXX0XX
B
CMDDELAY is not multiplied.
XXXX1XX
B
CMDDELAY is multiplied by CMULT.
XXX0XXX
B
BURSTC is not multiplied.
XXX1XXX
B
BURSTC is not multiplied.
XX0XXXX
B
DATAC is not multiplied.
XX1XXXX
B
DATAC is not multiplied.
X0XXXXX
B
RDRECOVC is not multiplied.
X1XXXXX
B
RDRECOVC is multiplied by CMULT.
0XXXXXX
B
WRRECOVC is not multiplied.
1XXXXXX
B
WRRECOVC is multiplied by CMULT.
Note that the bus access parameters WAITRDC,
WAITWRC, DTARDWR, and DTACS in register
BUSAPx are not programmable and always use the
CMULT multiplier.
WEAKPREF 8rwWeak Prefetch
0
B
Code prefetch cannot be aborted by an
interrupting data access.
1
B
Code prefetch can be aborted by an
interrupting data access.
AALIGN 9rwAddress Alignment
0
B
The EBU always issues a byte address when
performing an external bus access via this chip
select.
1
B
The EBU aligns the address according to the
setting of the PORTW bit field.
(see Section 13.5.7)
CTYPE [11:10] rw Cycle Type
This bit field is 00
B
after reset. In the TC1796, CTYPE
must always be written with 00
B
.
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