User's Manual

Table Of Contents
SYSTEM CONTROLLER S3C2450X RISC MICROPROCESSOR
2-36
8.7 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
S3C2450 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
TYPE_I [7:6] Priority type for AHB-Image bus 0x0
RESERVED [5:3] - 0x0