Panasonic MN103001G/F01K - Manual (Page 140)

Bus Controller (BC)
8-26
8.7 Space Partitioning
In extension memory mode (MMOD 1 to 0 = "LH"), the 1 GB memory space from x'80000000 to x'BFFFFFFF
becomes external memory space; in processor mode (MMOD 1 to 0 = "HL"), the 2 GB memory space from
x'40000000 to x'BFFFFFFF becomes external memory space. External memory space is partitioned into 4 blocks
(block 0 to block 3). When any of these blocks are accessed, various signals (such as CSn) corresponding to the
block in question are output. Fig. 8-7-1 shows the address format for external memory accesses, and Fig. 8-7-2
shows the memory map.
In addition, if it is necessary to extend the external memory space, extension address A23 (dual-purpose pin that is
shared with CS3) can be used to extend the memory space. (There is no portion for address extension for block 3.)
Fig. 8-7-1 Address Format When Accessing External Memory
In addition, the features of each block are described in Table 8-7-1. The various settings for each block are made
through the memory block 0 to 3 control registers and, when DRAM is connected, through the DRAM control
register.
Table 8-7-1 Features of Each Block
Block DRAM Bus Wait Mode Output signal used for Address data pins
connection width block identification separate/multiplex
Block 0 Not 8/16 Fixed Synchronous CS0 Permitted
permitted /asynchronous
Block 1 Permitted 8/16 Fixed Synchronous CS1 or RAS1 Permitted
/asynchronous
Block 2 Permitted 8/16 Fixed/handshaking Synchronous CS2 or RAS2 Permitted
/asynchronous
Block 3 Not 8/16 Fixed/handshaking Synchronous CS3 Permitted
Permitted /asynchronous
For details, refer to the descriptions of memory control registers 0A/B, 1A/B, 2A/B, and 3A/B in section 8.6,
“Description of Registers.”
Note 1. Handshaking can only be used in synchronous mode.
2. Connected DRAM can only be used when address and data are separate.
Address
31 30 29 28 27 26 25 24 23 22
Space partition unused unused
Block partition External address (8 MB space)
0
Extension address
00 : Block0
01 : Block1
10 : Block2
11 : Block3
00: Internal memory
01: Internal memory (when MMOD 1 to 0 = “LH”), External memory (when MMOD 1 to 0 = “HL”)
10: External memory
11: Access prohibited