Preliminary
S3C2451X RISC MICROPROCESSOR
SYSTEM CONTROLLER
2-35
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
BUS CONFIGURATION REGISTER (BUSPRI0, BUSPRI1, AND BUSMISC)
To improve AHB bus performance, software must control the arbitration scheme and type.
Register Address
R/W
Description
Reset
Value
BUSPRI0 0x4C00_0050
R/W
Bus
priority control register 0
0x0000_0000
S3C2451x consists of 2 hierarchical AHB buses. The arbitration priority and order can be configured with
BUSPRI0 registers. You can see specific priority number that assigned to each AMBA master in User’s Manual
section ‘04-BUS PRIORITIES’. The number of masters of AHB-S and AHB-I bus is 16 and 9 respectively.
Each TYPE field of BUSPRI0 register has three possible choices as follows:
1. 2’b00: the fixed type
2. 2’b01: the last granted maser has the lowest priority
3. 2’b10: the rotated type
4. 2’b11:
undefined
BUSPRI0 Bit
Description
Initial
Value
RESERVED [31:16] -
0x0000
TYPE_S
[15:14]
Priority type for AHB-System bus
0x0
RESERVED [13:12] -
0x0
ORDER_S [11:8]
Fixed priority order for AHB-S bus
Value Priority Value
Priority
4’h0
0-1-2-3-4-5-6-7-8-9-10-11-
12-13-14-15
4’h8
8-9-10-11-12-13-14-15-0-1-
2-3-4-5-6-7
4’h1
1-2-3-4-5-6-7-8-9-10-11-12-
13-14-15-0
4’h9
9-10-11-12-13-14-15-0-1-2-
3-4-5-6-7-8
4’h2
2-3-4-5-6-7-8-9-10-11-12-13-
14-15-0-1
4’ha
10-11-12-13-14-15-0-1-2-3-
4-5-6-7-8-9
4’h3
3-4-5-6-7-8-9-10-11-12-0-1-2
4’hb
11-12-13-14-15-0-1-2-3-4-
5-6-7-8-9-10
4’h4
4-5-6-7-8-9-10-11-12-13-14-
15-0-1-2-3
4’hc
12-13-14-15-0-1-2-3-4-5-6-
7-8-9-10-11
4’h5
5-6-7-8-9-10-11-12-13-14-
15-0-1-2-3-4
4’hd
13-14-15-0-1-2-3-4-5-6-7-8-
9-10-11-12
4’h6
6-7-8-9-10-11-12-13-14-15-
0-1-2-3-4-5
4’he
14-15-0-1-2-3-4-5-6-7-8-9-
10-11-12-13
4’h7
7-8-9-10-11-12-13-14-15-0-
1-2-3-4-5-6
4’hf
15-0-1-2-3-4-5-6-7-8-9-10-
11-12-13-14
0x0