r8a77850anbg Renesas Electronics Corporation., r8a77850anbg Datasheet - Page 237

• Manufacturer Part Number: r8a77850anbg
• Description: Renesas 32-bit Risc Microcomputer Superh? Risc Engine Family
• Manufacturer: Renesas Electronics Corporation.

7.9
The address mode of this LSI after a power-on reset or manual reset can be switched between 29-
bit address mode and 32-bit address extended mode by specifying external pins. The following
changes apply when this LSI is booted up in 32-bit address extended mode.
7.9.1
When 32-bit address extended mode is specified by external pins, the following initial entries are
recorded in the PMB after a power-on reset or manual reset, and the SE bit in the PASCR register
is initialized to 1. For entries 2 to 15, only the V bit is initialized to 0.
7.9.2
Immediately after a power-on or manual reset, the P1 or P2 area is mapped to the PMB. Therefore,
when an area other than that indicated by the initial entry needs to be mapped, follow the
procedures below to modify the PMB, taking care not to generate PMB misses and multiple PMB
hits. The procedure should be set up within the boot routine and should be executed before
activation of the caches and TLB (CCR.ICE = 1, CCR.OCE = 1, and MMUCR.AT = 1). Do not
use routines other than the boot routine to change the value recorded in the PMB.
(1)
1. Read the initial entry, change only the SZ bits to reduce the page size, and save the new value
2. Invalidate the entry remaining in the ITLB that corresponds to the PMB by writing 1 to the TI
3. In the memory-mapped PMB, record PMB entries to fill the P1 or P2 area in which the PMB
4. Execute one of the following steps, A, B, and C. Do not execute a branch or operand access for
Entry
0
1
over the previous entry. The program that changes the PMB should be allocated within 1
Mbyte of the top of the page with the reduced size.
bit in the MMUCR register.
translation information is evicted by step 1.
the P1 or P2 area in which the PMB translation information is evicted by step 1.
A. Perform a branch using the RTE instruction.
B. Execute the ICBI instruction for any address (including non-cacheable area).
When the Program Modifying the PMB is in the P1 or P2 Area
32-Bit Boot Function
Initial Entries to PMB
Notes on 32-Bit Boot
VPN[31:24] PPN[31:24]
10000000
10100000
00000000
00000000
V
1
1
SZ[1:0]
11
11
Rev.1.00 Jan. 10, 2008 Page 207 of 1658
7. Memory Management Unit (MMU)
C
1
0
UB
0
0
REJ09B0261-0100
WT
1
0