CHAPTER 5 MEMORY ACCESS CONTROL FUNCTION
User’s Manual U12688EJ4V0UM00
138
5.3.3 Address multiplex function
Depending on the value of the DAW0n and DAW1n bits in DRAM configuration register n (DRCn), the row address,
column address output in the DRAM cycle is multiplexed as shown in Figure 5-7 (n = 0 to 3). In Figure 5-7, a0 to a23
show the addresses output from the CPU and A0 to A23 show the V850E/MS1’s address pins. For example, when
DAW0n and DAW1n = 11, it indicates that a12 to a22 are output from the address pins (A1 to A11) as row addresses
and a1 to a11 are output as column addresses.
Table 5-1 shows the relationship between connectable DRAM and the address multiplex width. Depending on the
DRAM being connected, DRAM space is from 128 KB to 8 MB.
Figure 5-7. Row Address/Column Address Output
Row address
(DAW1n, DAW0n = 11)
Address pin
A23 to A18
a23 to a18
A17
a17
A16
a16
A15
a15
A14
a25
A13
a24
A12
a23
A11
a22
A10
a21
A9
a20
A8
a19
A7
a18
A6
a17
A5
a16
A4
a15
A3
a14
A2
a13
A1
a12
A0
a11
Row address
(DAW1n, DAW0n = 10)
a23 to a18 a17 a16 a25 a24 a23 a22 a21 a20 a19 a18 a17 a16 a15 a14 a13 a12 a11 a10
Row address
(DAW1n, DAW0n = 01)
a23 to a18 a17 a25 a24 a23 a22 a21 a20 a19 a18 a17 a16 a15 a14 a13 a12 a11 a10 a9
Row address
(DAW1n, DAW0n = 00)
a23 to a18 a25 a24 a23 a22 a21 a20 a19 a18 a17 a16 a15 a14 a13 a12 a11 a10 a9
a8
Column address
a23 to a18 a17 a16 a15 a14 a13 a12 a11 a10 a9
a8
a7
a6
a5
a4
a3
a2
a1
a0
Table 5-1. Example of DRAM and Address Multiplex Width
DRAM Capacity (Bits) and Configuration
Address
Multiplex Width
256 K
1 M
4 M
16 M
64 M
DRAM Space
(Bytes)
8 bits
64 K
×
4
128 K
256 K
×
4
256 K
×
16
512 K
512 K
×
8
1 M
9 bits
4 M
×
16
8 M
1 M
×
4
1 M
×
16
2 M
2 M
×
8
4 M
10 bits
4 M
×
16
8 M
11 bits
4 M
×
4
8 M
Содержание V850E/MS1 UPD703100
Страница 2: ...User s Manual U12688EJ4V0UM00 2 MEMO ...
Страница 6: ...User s Manual U12688EJ4V0UM00 6 MEMO ...
Страница 8: ...User s Manual U12688EJ4V0UM00 8 MEMO ...
Страница 12: ...User s Manual U12688EJ4V0UM00 12 MEMO ...
Страница 26: ...User s Manual U12688EJ4V0UM00 26 MEMO ...
Страница 68: ...User s Manual U12688EJ4V0UM00 68 MEMO ...
Страница 124: ...User s Manual U12688EJ4V0UM00 124 MEMO ...
Страница 198: ...User s Manual U12688EJ4V0UM00 198 MEMO ...
Страница 230: ...User s Manual U12688EJ4V0UM00 230 MEMO ...
Страница 422: ...User s Manual U12688EJ4V0UM00 422 MEMO ...