Chapter 7 External Bus Controller
7-22
Bit Mnemonic Field
Name
Description
Read/Write
17:16 PWT Page Mode
Wait time
External Bus Control Page Mode Wait Time (Default: 11 / 00)
Specifies the wait cycle count during Burst access when in the Page mode.
00: 0 wait cycles
10: 2 wait cycles
01: 1 wait cycle
11: 3 wait cycles
Specifies a wait cycle count from 0 to 62 that matches WT when in the
Normal mode or Ready mode. (See the WT item.)
R/W
15:12 WT Normal Mode
Wait Time
External Bus Control Normal Mode Wait Time
(Default: 111 (~DATA[4])/0000)
Specifies the wait cycle count in the first cycle of a Single Cycle or Burst
access.
Specifies the following wait cycle count when in the Page mode.
0000: 0 wait cycles
0100: 4 wait cycles
1000: 8 wait cycles
1100: 12 wait cycles
0001: 1 wait cycle
0101: 5 wait cycles
1001: 9 wait cycles
1101: 13 wait cycles
0010: 2 wait cycles
0110: 6 wait cycles
1010: 10 wait cycles
1110: 14 wait cycles
0011: 3 wait cycles
0111: 7 wait cycles
1011: 11 wait cycles
1111: 15 wait cycles
Specifies a wait cycle count from 0 to 62 that matches PWT when in a mode
other than the Page mode.
PWT[1:0]: WT[3:0]
000000: 0 wait cycles 010000: 16 wait cycles 110000: 48 wait cycles
000001: 1 wait cycle
010001: 17 wait cycles 110001: 49 wait cycles
: : :
001110: 14 wait cycles 011110: 30 wait cycles 111110: 62 wait cycles
001111: 15 wait cycles 011111: 31 wait cycles 111111: External ACK mode
Note 1: Value that is the reverse of DATA[4] is set to the LSB of Channel 0
as the default.
Note 2: If PWT:WT is set to 0x3f when PM = 00 and RDY = 0, the external
bus enters the ACK
*
Input mode (External ACK mode) without the
wait cycle count for the ACK
*
output being the maximum value.
Note 3: WT[0] is used to select Dynamic/Static ACK
*
/Ready mode when in
the Ready mode. Therefore, the Wait cycle count is an even
number.
Note 4: The WT wait cycle count should be equal to or greater than the
PWT Wait cycle count when in the Page mode.
R/W
11:8
CS
Channel Size
External Bus Control Channel Size (Default: 0010/0000)
Specifies the channel memory size.
0000: 1 MB
0101: 32 MB
*
1010: 1 GB
0001: 2 MB
0110: 64 MB
1011-1111: Reserved
0010: 4 MB
0111: 128 MB
0011: 8 MB
1000: 256 MB
0100: 16 MB
1001: 512 MB
*
The channel memory size can be set up to 512 MB when the memory bus
width is 16 bits, or up to 256 MB when the memory bus width is 8 bits. No
size larger than this can be set.
R/W
7
BC
Byte Control
External Bus Byte Control (Default: DATA[5]/0)
Specifies whether to use the BWE
*
[3:0] signal as an asserted Byte Write
Enable signal (BWE
*
[3:0]) only during a Write cycle, or to use it as an
asserted Byte Enable signal (BE
*
[3:0]) that is asserted during both Read
and Write cycles.
0: Byte Enable (BE
*
[3:0])
1: Byte Write Enable (BWE
*
[3:0])
Note: DATA[5] is set to Channel 0 as the default.
R/W
Figure 7.4.1 External Bus Channel Control Register (2/3)
Summary of Contents for TX49 TMPR4937
Page 1: ...64 Bit TX System RISC TX49 Family TMPR4937 Rev 2 0 ...
Page 4: ......
Page 13: ...Table of Contents ix TMPR4937 Revision History 1 ...
Page 14: ...Table of Contents x ...
Page 15: ...Handling Precautions ...
Page 16: ......
Page 18: ...1 Using Toshiba Semiconductors Safely 1 2 ...
Page 40: ...3 General Safety Precautions and Usage Considerations 3 18 ...
Page 42: ...4 Precautions and Usage Considerations 4 2 ...
Page 43: ...TMPR4937 2005 3 Rev 2 0 ...
Page 44: ......
Page 52: ...Chapter 1 Overview and Features 1 6 ...
Page 156: ...Chapter 7 External Bus Controller 7 56 ...
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Page 506: ...Chapter 20 Extended EJTAG Interface 20 8 ...
Page 530: ...Chapter 22 Pinout and Package Information 22 10 ...
Page 542: ...Chapter 24 Parts Number when Ordering 24 2 ...