Preliminary
I/O PORTS
S3C2451X RISC MICROPROCESSOR
11-12
PORT B CONTROL REGISTERS (GPBCON, GPBDAT, GPBUDP, GPBSEL)
Register Address
R/W
Description
Reset
Value
GPBCON
0x56000010
R/W
Configures the pins of port B
0x0
GPBDAT
0x56000014
R/W
The data register for port B
0x0
GPBUDP 0x56000018 R/W
Pull-up/down
control register for port B
0x00154555
GPBSEL
0x5600001c
R/W
Selects the function of port B
0x1
GPBCON Bit
Description
Reserved [31:22]
Reserved
GPB10
[21:20]
00 = Input
01 = Output
10 = nXDREQ[0] 11 = XDREQ[0]
GPB9
[19:18]
00 = Input
01 = Output
10 = nXDACK[0] 11 = XDACK[0]
GPB8
[17:16]
00 = Input
01 = Output
10 = nXDREQ[1] 11 = XDREQ[1]
GPB7
[15:14]
00 = Input
01 = Output
10 = nXDACK[1] 11 = XDACK[1]
GPB6
[13:12]
00 = Input
01 = Output
10 = nXBREQ 11 = XBREQ
GPB5
[11:10]
00 = Input
01 = Output
10 = nXBACK
11 = XBACK
GPB4
[9:8]
00 = Input
01 = Output
10 = TCLK
11 = reserved
GPB3
[7:6]
00 = Input
01 = Output
10 = TOUT3 11 = reserved
GPB2
[5:4]
00 = Input
01 = Output
10 = TOUT2 11 = reserved
GPB1
[3:2]
00 = Input
01 = Output
10 = TOUT1 11 = reserved
GPB0
[1:0]
00 = Input
01 = Output
10 = TOUT0 11 = reserved