External Bus Interface (EBI)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
29-10
Freescale Semiconductor
Preliminary
consumption. The clock signal dedicated to the registers, however, allows access to the registers even
while the EBI is in the module disable mode. Flag bits in the EBI transfer error status register (EBI_TESR),
however, are set and cleared with the clock used by the non-register portion of the EBI. Consequently, in
module disable mode, the EBI_TESR does not have a clock signal and is therefore not writable.
29.3.2.3
EBI Module Configuration Register (EBI_MCR)
The EBI_MCR contains bits that configure various attributes associated with EBI operation.
Offset: 0x0000
Access: User read/write
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R ACG
E
EXT
M
EARB
0
1
0
0
0
0
MDIS
0
0
0
D16_
31
AD_
MUX
DBM
W
Reset
0
0
0
0
1
0
0
0
0
0
0
0
0
1
1
0
Figure 29-2. EBI Module Configuration Register (EBI_MCR)
Table 29-4. EBI_MCR Field Descriptions
Field
Description
bits 0–15
Reserved.
ACGE
Automatic CLKOUT Gating Enable. Enables the EBI feature of turning off CLKOUT (holding it high) during idle
periods in-between external bus accesses.
0 Automatic CLKOUT gating is disabled.
1 Automatic CLKOUT gating is enabled.
EXTM
External Master Mode.
0 External master mode is inactive (single master mode).
1 External master mode is active.
Note: EXTM=1 is not supported on MPC5510.
EARB
External Arbitration. When EXTM = 0, the EARB bit is a don’t care, and is treated as 0.
0 Internal arbitration is used.
1 External arbitration is used.
bits 19–24
Reserved.
Note: Reserved bits 19-20 are writeable, but writing to these bits have no effect other than to update the value
of the register. For future compatibility, this bit should be written to zero.
MDIS
Module Disable Mode. Allows the clock to be stopped to the non-memory mapped logic in the EBI, effectively
putting the EBI in a software controlled power-saving state. See
Section 29.1.3.3, “Module Disable Mode
,” for
more information. No external bus accesses can be performed when the EBI is in module disable mode
(MDIS = 1).
0 Module disable mode is inactive.
1 Module disable mode is active.
bits 26–28
Reserved.