
3.0 Device Architecture and Configuration
(Continued)
Revision 1.2
41
www.national.com
P
Table 13. Interrupt Configuration Registers
Table 14. DMA Configuration Registers
Index
Register Name
Description
70h
Interrupt Number
and Wake-Up on
IRQ Enable
Indicates selected interrupt number.
Bits 7-5 - Reserved.
Bit 4 - Enables a Power Management event (SCI or wake-up) from the IRQ of the
logical device. When enabled, IRQ assertion sets the respective
XXX
_IRQ_STS bit
(
XXX
is MOD, MS or KBD) in the GPE1_STS_3 register (see Section 9.4.11 on
page 211).
0: Disabled (default)
1: Enabled
Note:
If the BIOS routine that sets IRQ does not use a Read-Modify-Write
sequence, it might reset bit 4. To ensure that the system wakes up, the BIOS must
set bit 4 before the system goes to sleep.
Bits 3-0 select the interrupt number. A value of 1 selects IRQ1. A value of 15
selects IRQ15. IRQ0 is not a valid interrupt selection and represents no interrupt
selection.
Note:
Avoid selecting the same interrupt number (except 0) for different Logical
Devices, as it causes the PC8741x device to behave unpredictably.
71h
Interrupt Request
Type Select
Indicates the type and polarity of the interrupt request number selected in the
previous register. If a logical device supports only one type of interrupt, the
corresponding bit is read-only.
Bits 7-2 - Reserved.
Bit 0 - Type of interrupt request selected in previous register
0: Edge
1: Level
Bit 1 - Polarity of interrupt request selected in previous register
0: Low polarity
1: High polarity
Index
Register Name
Description
74h
DMA Channel
Select 0
Indicates selected DMA channel for DMA 0 of the logical device (0 - The first DMA
channel in case of using more than one DMA channel).
Bits 7-3 - Reserved.
Bits 2-0 select the DMA channel for DMA 0. The valid choices are 0-3, where:
- A value of 0 selects DMA channel 0, 1 selects channel 1, etc.
- A value of 4 indicates that no DMA channel is active.
- The values 5-7 are reserved.
Note:
Avoid selecting the same DMA channel (except 4) for different Logical
Devices, as it causes the PC8741x device to behave unpredictably.
75h
DMA Channel
Select 1
Indicates selected DMA channel for DMA 1 of the logical device (1 - The second
DMA channel in case of using more than one DMA channel).
Bits 7-3 - Reserved.
Bits 2-0 select the DMA channel for DMA 1. The valid choices are 0-3, where:
- A value of 0 selects DMA channel 0, 1 selects channel 1, etc.
- A value of 4 indicates that no DMA channel is active.
- The values 5-7 are reserved.
Note:
Avoid selecting the same DMA channel (except 4) for different Logical
Devices, as it causes the PC8741x device to behave unpredictably.