External Bus Interface (EBI)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
29-9
Preliminary
29.3.2
Register Descriptions
This section lists some special considerations for EBI registers and then the EBI registers in address order,
describing the registers and their bit fields.
29.3.2.1
Writing EBI Registers While a Transaction is in Progress
Other than the exceptions noted below, EBI registers must not be written while a transaction to the EBI
(from internal master) is in progress (or within 2 CLKOUT cycles after a transaction has just completed,
to allow internal state machines to go IDLE). In such cases, the behavior is undefined.
Exceptions that can be written while an EBI transaction is in progress are the following:
•
All bits in EBI_TESR
If code in external memory needs to write EBI registers, this must be done in a way that avoids modifying
EBI registers while external accesses are being performed, such as the following method:
•
Copy the code that is doing the register writes (plus a return branch) to internal SRAM
•
Branch to internal SRAM to run this code, ending with a branch back to external flash
29.3.2.2
Separate Input Clock for Registers
The EBI registers are accessed with a clock signal separate from the clock used by the rest of the EBI. In
module disable mode, the clock used by the non-register portion of the EBI is disabled to reduce power
Table 29-3. EBI Memory Map
Offset from
EBI_BASE
(0xFFFF_4000)
Register
Access
Reset Value
Section/Page
0x0000
EBI_MCR — EBI module configuration register
R/W
1
1
All bits may not be writeable. See register description.
0x0000_0804
0x0004
Reserved
0x0008
EBI_TESR — EBI transfer error status register
0x0000_0000
0x000c
EBI_BMCR — EBI bus monitor control register
0x0000_FF80
0x0010
EBI_BR0 — EBI base register bank 0
R/W
0x2000_0042
0x0014
EBI_OR0 — EBI option register bank 0
R/W
0xE000_0000
0x0018
EBI_BR1 — EBI base register bank 1
R/W
0x2000_0042
0x001C
EBI_OR1 — EBI option register bank 1
R/W
0xE000_0000
0x0020
EBI_BR2 — EBI base register bank 2
R/W
0x2000_0042
0x0024
EBI_OR2 — EBI option register bank2
0xE000_0000
0x0028
EBI_BR3 — EBI base register bank 3
R/W
0x2000_0042
0x002C
EBI_OR3 — EBI option register bank 3
R/W
0xE000_0000
0x0020–0x005C
Reserved
