261
Bus and Memory Control (BCU, MEMC)
Chapter 7
Preliminary User’s Manual U17566EE1V2UM00
7.3.1
BCU registers
The following registers are part of the BCU. They define the usage of the
programmable peripheral I/O area (PPA), the data bus width, the endian format
of word data, and they control access to external devices.
(1)
BPC - Peripheral area selection control register
The 16-bit BPC register defines whether the programmable peripheral I/O area
(PPA) is used or not and determines the starting address of the PPA.
Access
This register can be read/written in 16-bit units.
Address
FFFF F064
H
Initial Value
0000
H
Caution
Bit 14 must always be 0.
The base address PBA of the programmable peripheral area sets the start
address of the 16 KB PPA in a range of 256 MB. The 256 MB page is mirrored
16 times to the entire 32-bit address range.
The base address PBA is calculated by
PBA = BPC.PA[13:0] x 2
14
Table 7-8 shows how the base address PBA of the programmable peripheral
area is assembled.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PA15
0
PA13 PA12 PA11 PA10
PA9
PA8
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
Table 7-7
BPC register contents
Bit Position
Bit Name
Function
15
PA15
Select usage of programmable peripheral I/O area (PPA).
0: PPA disabled
1: PPA enabled
13 to 0
PA[13:0]
Bits PA[13:0] specify bits 27 to 14 of the starting address of the PPA. The other bits
of the address are fixed to 0.
Table 7-8
Address range of programmable peripheral area (16 KB)
31
…
28
27
…
14
13
…
1
0
bit
0
…
0
BPC.PA[13:0]
1
…
1
1
…
…
…
0
…
0
BPC.PA[13:0]
0
…
0
1
0
…
0
BPC.PA[13:0]
0
…
0
0
PBA
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