REG OFFSET
(hex)
NAME
DESCRIPTION
General Purpose I/0 bit 2.1
GP21
2C
Bit[0] In/Out : =1 Input, =0 Output
Bit[1] Polarity : =1 Invert, =0 No Invert
Bit[3:2] Alternate Function Select
11=Reserved
Default =0x01
on VTR POR
(R/W)
10=Either Edge Triggered Interrupt Input 0 (Note 1)
01=8042 P16 function (User Note 2)
00=Basic GPIO function
Bits[6:4] Reserved
Bit[7] Output Type Select
1=Open Drain
0=Push Pull
GP22
2D
General Purpose I/0 bit 2.2
Bit[0] In/Out : =1 Input, =0 Output
Bit[1] Polarity : =1 Invert, =0 No Invert
Bit[3:2] Alternate Function Select
11= nMRT1 – floppy motor select 1 (Note 3)
10= Either Edge Triggered Interrupt Input 1 (Note 1)
01=8042 P12 function (User Note 2)
00=Basic GPIO function
Bits[6:4] Reserved
Default =0x01
on VTR POR
(R/W)
Bit[7] Output Type Select
1=Open Drain
0=Push Pull
GP23
2E
General Purpose I/0 bit 2.2
Bit[0] In/Out : =1 Input, =0 Output
Bit[1] Polarity : =1 Invert, =0 No Invert
Bit[2] Alternate Function Select
1= IRQIND (IRQ Input D)
0= Basic GPIO Function
Bits[6:3] Reserved
Default=0x01
on VTR POR
(R/W)
Bit[7] Output Type Select
1=Open Drain
0=Push Pull
GP24
2F
General Purpose I/0 bit 2.4
Bit[0] In/Out : =1 Input, =0 Output
Bit[1] Polarity : =1 Invert, =0 No Invert
Bit[2] Alternate Function Select
1=P17
Default = 0x01
on VTR POR
(R/W)
0=GPIO
Bits[6:3] Reserved
Bit[7] Output Type Select
1=Open Drain
0=Push Pull
SMSC LPC47S45x
Page 174 of 259
Rev. 06-01-06
DATASHEET
SMSC [ SMSC CORPORATION ]
