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PC/104 DIGITAL I/O DIO1-PC/104

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The DIO1 digital I/O channels and registers are I/O port mapped to the PC/104 host system I/O address space. The I/O base address is jumper selectable with jumper JP1 to 200h, 220h, 280h, 2A0h, 300h, 320h, 380h, or 3A0h. The digital input channels can generate an interrupt request to the PC/104 bus. This interrupt request is jumper selectable with jumper JP2 on the PC/104 bus interrupts IRQ2, IRQ3, IRQ4, IRQ5, IRQ6, or IRQ7 with the 8- bit PC/104 DIO1 version. On the 16- bit version the interrupt request is jumper selectable on the PC/104 bus interrupts IRQ2, IRQ3, IRQ4, IRQ5, IRQ6, IRQ7, IRQ10, IRQ11, IRQ12, IRQ14, or IRQ15. The DIO1 jumper configuration with the jumpers JP1 and JP2 is important for using the DIO1 in PC/104 based embedded systems together with real- time operating systems (RTOS). Most of this operating systems do not use the Plug and Play methods.

Each DIO1 relay output is on by writing a ´1´ to the relay output registers ROUTL (Relay OUTput Low byte) and ROUTH (Relay OUTput High byte). Each relay output is off by writing a ´0´ to the same registers. On power up or reset the output latches that drive the relay drivers are off and ROUTL= ROUTH= 00h. The DIO1 also offers an output channel watchdog. On power up or reset the output channel watchdog is disabled. For using this watchdog the application software must set the watchdog mode bits WMD0 and WMD1 in the DIO1 CTRL (ConTRoL) register. If the output channel watchdog is enabled, the application software must trigger this watchdog every 150 msec., 600 msec., or 1200 msec. If the software do not trigger the output channel watchdog, the watchdog resets ROUTL= ROUTH= 00h and each relay output is off.

The current status of each DIO1 opto-isolated digital input is read from the input registers DINPL (Digital INPut Low byte) and DINPH (Digital INPut High byte). The DIO1 input channels can generate a system interrupt request which can be routed via jumper JP2 to the PC/104 bus. The input channel interrupt logic offers two different interrupt modes: 1. the input channel change interrupt and 2. the input channel value interrupt.

The DIO1 offers connectors for 8-bit (J1) or 16-bit PC/104 (J1/J2) in stackthrough or non- stackthrough version. The opto- isolated digital input channels are wired to a 34- pin connector. The relay output channels of the DIO1 are wired to one 34- pin connector and one 16- pin connector.