IBM BDM-610000049 user manual Advanced Digital Interrupts, Event Mode, Match Mode

Table 50 Wake Control I/O Address 451h

D7	D6	D5	D4	D3	D2	D1	D0
		Reserved				Int Mask	Wake Enable
						1 = Interrupt is masked	1=Interrupt triggers a Wake Event
						0=Interrupt is enabled	0=Interrupt does not trigger a wake event.

Port 1 Data register is a read/write byte direction

Interrupts

In order to use an interrupt with aDIO, the interrupt must first be selected in the BIOS setup utility under Advanced, I/O Devices, aDIO Configuration, aDIO Interrupt. The Digital I/O can use interrupts 3, 5, 6, 7, 10, 11, and 12. The interrupt must also be reserved so that is it not assigned to PCI devices. To reserve the interrupt, enter the BIOS under PCIPnP and change the interrupt you wish to use to “Reserved.” Then, select the appropriate interrupt mode in the DIO Control register. Also, verify that the Int Mask bit is cleared in the Wake Control register

Advanced Digital Interrupts

There are three Advanced Digital Interrupt modes available. These three modes are Event, Match, and Strobe. The use of these three modes is to monitor state changes at the aDIO connector. Interrupts are enabled by writing to the Digital IRQ Mode field in the DIO-Controlregister.

Event Mode

When this mode is enabled, Port 0 is latched into the DIO-Compare register at 8.33 MHz. The aDIO circuitry includes deglitching logic. The deglitching requires pulses on Port 0 to be at least 120 ns in width. As long as changes are present longer than that, the event is guaranteed to register. Pulses as small as 60 ns can register as an event, but they must occur between the rising and falling edge of the 8.33 MHz clock. To enter Event mode, set bits [4:3] of the DIO-Control register to “10”.

Match Mode

When this mode is enabled, Port 0 is latched into the DIO-Compare register at 8.33 MHz. The aDIO circuitry includes deglitching logic. The deglitching requires pulses on Port 0 to be at least 120 ns in width. As long as changes are present longer than that, the match is guaranteed to register. Pulses as small as 60 ns can register as a match, but they must occur between the rising and falling edge of the 8.33 MHz clock. To enter Match mode, set bits [4:3] of the DIO-Control register to “11”.

Note Make sure bits [4:3] are set BEFORE writing the DIO-Compare register. If you do not set them first, the contents of the DIO-Compare register could be lost because the Event mode latches in Port 0 into the DIO-Compare register.

64 CMX158886 cpuModule BDM-610000049 Rev G