Internal Memory Map Register (Immr) - Motorola MPC8260 PowerQUICC II User Manual

Part II. ConÞguration and Reset

4.3.2.7 Internal Memory Map Register (IMMR)

The internal memory map register (IMMR), shown in Figure 4-29, contains identiÞcation
of a speciÞc device as well as the base address for the internal memory map. Software can
deduce availability and location of any on-chip system resources from the values in IMMR.
PARTNUM and MASKNUM are mask programmed and cannot be changed for any
particular device.
Bit 0 1 2
Field
Reset Depends on reset conÞguration sequence. See Section 5.4.1, ÒHard Reset ConÞguration Word.Ó
R/W
Addr
Bit 16 17 18
Field
Reset
R/W
Addr
Figure 4-29. Internal Memory Map Register (IMMR)
Table 4-13 describes IMMR Þelds.
Bits Name
0Ð14 ISB Internal space base. DeÞnes the base address of the internal memory space. The value of ISB
be conÞgured at reset to one of 32 addresses; it can then be changed to any value by the
software. The default is 0, which maps to address 0x0000_0000.
ISB deÞnes the 15 msbs of the memory map register base address. IMMR itself is mapped in
the internal memory space region. As soon as the ISB is written with a new base address, the
IMMR base address is relocated according to the ISB. ISB can be conÞgured to one of 32
possible addresses at reset to enable the conÞguration of multiple-MPC8260 systems.
The number of programmable bits in this Þeld, and hence the resolution of the location of
internal space, depends on the internal memory space of a speciÞc implementation. In the
MPC8260, all 15 bits can be programmed. See Chapter 3, ÒMemory Map,Ó for details on the
deviceÕs internal memory map and to Chapter 5, ÒReset,Ó for the available, default initial values.
15 Ñ Reserved, should be cleared.
16Ð23 PARTNUM Part number. This read-only Þeld is mask-programmed with a code corresponding to the part
number of the part on which the SIU is located. It is intended to help factory test and user code
which is sensitive to part changes. This changes when the part number changes. For example,
it would change if any new module is added or if the size of any memory module is changed. It
would not change if the part is changed to Þx a bug in an existing module. The MPC8260 has an
ID of 0x00.
24Ð31 MASKNUM Mask number. This read-only Þeld is mask-programmed with a code corresponding to the mask
number of the part on which the SIU is located. It is intended to help factory test and user code
which is sensitive to part changes. It is programmed in a commonly changed layer and should
be changed for all mask set changes. The MPC8260 (Rev 0) has an ID of 0x00.
4-34
3 4 5 6
19 20 21 22
PARTNUM
Table 4-13. IMMR Field Descriptions
MPC8260 PowerQUICC II UserÕs Manual
7 8 9 10
ISB
R/W
0x101A8
23 24 25 26
MASKNUM
Ñ
R
0x101AA
Description
11 12 13 14
27 28 29 30
MOTOROLA
15
Ñ
31