LPC47N237-MD SMSC [SMSC Corporation], LPC47N237-MD Datasheet - Page 105

• Manufacturer Part Number: LPC47N237-MD
• Description: 3.3V I/O CONTROLLER FOR PORT REPLICATORS AND DOCKING STATIONS
• Manufacturer: SMSC [SMSC Corporation]

3.3v I/O Controller for Port Replicators and Docking Stations
17.4.27 CR26
17.4.28 CR27
SMSC DS – LPC47N237
CR26 can only be accessed in the configuration state and after the CSR has been initialized to 26H. CR26
is used to select the DMA for the Parallel Port (bits 0 - 3). Any unselected DMA Request output (DRQ) is in
tristate.
CR27 can only be accessed in the configuration state and after the CSR has been initialized to 27H. CR27
is used to select the IRQ for the Parallel Port (bits 3 - 0). Any unselected IRQ output (registers CR27 -
CR29) is in tri-state.
BIT NO.
BIT NO.
3:0
7:4
3:0
7:4
PP DMA Select
PP IRQ Select
Type: R/W
Type: R/W
BIT NAME
BIT NAME
Reserved
Reserved
These bits are used to select DMA for Parallel Port.
Read Only. A read returns 0.
BITS[3:0]
BITS[7:4]
These bits are used to select IRQ for Parallel Port.
Read Only. A read returns 0.
Table 17.23 - DMA Selection
PP DMA Selection Register
PP IRQ Selection Register
DATASHEET
0000
0001
0010
0011
0100
1110
1111
OR
....
....
Table 17.22 - CR26
Table 17.24 - CR27
Page 105
RESERVED
RESERVED
RESERVED
SELECTED
NONE
DMA1
DMA2
DMA3
DMA
….
….
DESCRIPTION
DESCRIPTION
Default: 0x00 on VCC POR
Default: 0x00 on VCC POR
Revision 0.3 (10-26-04)