RM5231A-350-H PMC-Sierra Inc, RM5231A-350-H Datasheet - Page 27

• Manufacturer Part Number: RM5231A-350-H
• Description: RM5231A Microprocessor with 32-Bit System Bus Data Sheet Preliminary
• Manufacturer: PMC-Sierra Inc

Proprietary and Confidential to PMC-Sierra, Inc and for its Customer’s Internal Use
Document ID: PMC-2002174, Issue 2
3.32 Boot-Time Modes
Mode
bit
0
4:1
7:5
8
10:9
11
12
14:13
Immediately after the VccOK signal is asserted, the processor reads a serial bit stream of 256 bits
to initialize all the fundamental operational modes. ModeClock runs continuously from the
assertion of VccOK.
The boot-time serial mode stream is defined in Table 4. Bit 0 is the bit presented to the processor
as the first bit in the stream when VccOK is asserted. Bit 255 is the last bit transferred.
Table 4 Boot Time Mode Bit Stream
Description
Reserved: Must be zero
Write-back data rate (W = write data transfer, x = wait
state)
Pclock to SysClock Multiplier
Specifies byte ordering. Logically ORed with
BigEndian input signal.
Non-Block Write Protocol
Timer Interrupt Enable/Disable
Reserved: Must be zero
Output driver strength - 100% = fastest
Mode Bits 7:5
0: WWWWWWWW
1: WWxWWxWWxWWx
2: WWxxWWxxWWxxWWxx
3: WxWxWxWxWxWxWxWx
4: WWxxxWWxxxWWxxxWWxxx
5: WWxxxxWWxxxxWWxxxxWWxxxx
6: WxxWxxWxxWxxWxxWxxWxxWxx
7: WWxxxxxxWWxxxxxxWWxxxxxxWWxxxxxx
8: WxxxWxxxWxxxWxxxWxxxWxxxWxxxWxxx
9-15 reserved
0: Little endian
1: Big endian
00: R4000 compatible
01: reserved
10: pipelined
11: write re-issue
0: Enable the timer interrupt on Int5*
1: Disable the timer interrupt on Int5*
00: 67% strength
01: 50% strength
10: 100% strength
11: 83% strength
000
001
010
011
100
101
110
111
Multiply by 9
Multiply by 5
Multiply by 8
Multiply by 2
Multiply by 3
Multiply by 4
Multiply by 6
Multiply by 7
Mode Bit 20=0
Multiply by 4.5
Multiply by 2.5
Multiply by 3.5
Mode Bit 20=1
n/a
n/a
n/a
n/a
n/a
RM5231A™ Microprocessor with 32-Bit System Bus Data Sheet
Mode
bit
15
17:16
19:18
20
21
22
255:23 Reserved: Must be zero
Description
Reserved: Must be zero
System configuration identifiers - software
visible in Config[21..20] register
Reserved: Must be zero
Select SysClock to PClock Multiply Mode
Reserved: Must be one
VccIO Setting
0: Integer Multipliers
1: Half-Integer Multipliers
0: VccIO = 3.3V
1: VccIO = 2.5V
Preliminary
26