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
8
rw
Weak 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
9
rw
Address 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
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
.