Measurement-computing Personal488 rev.3.0 For DOS & Windows 3.Xi Uživatelský manuál stáhnout pdf (Strana 36)

5. Personal488/MM I. HARDWARE GUIDES

I-20 Personal488 User’s Manual, Rev. 3.0

Interrupt Selection

The GP488/MM interface board may be set to interrupt the PC on the occurrence of certain hardware

conditions. The level of the interrupt generated is set by JP3 on Rev. B boards (JP2 on Rev. A boards).

The GP488/MM interface board adheres to the “AT-style” interrupt sharing conventions. When an

interrupt occurs, the interrupting device must be reset by writing to I/O address

02FX

, where X is the

interrupt level (from 0-7). This interrupt response level is set by switches 1, 2, and 3 of SW1 which

must be set to correspond to the JP3 (Rev. B board) interrupt level setting. Interrupt selection for a

Rev. B board is illustrated in the following figure.

Note: The jumper label would read JP2 for Rev. A boards.

DMA Channel Selection

Direct Memory Access (DMA) is a high-speed method of

transferring data from or to a peripheral, such as a

digitizing oscilloscope, to or from the PC’s memory.

The factory default selection is DMA channel 1. Note

that jumper JP2 is used to configure revision B boards

while the jumper labeled JP3 is used to select the DMA

channel on version A boards.

Note: Check your computer documentation to ensure

the selected DMA channel is not being used by

another device. The GP488B/MM board has

circuitry which allows for more than one

GP488/MM board to share the same channel.

Most computers use DMA channel 2 for floppy

disk drives, making that channel unavailable.

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Measurement-computing Personal488 rev.3.0 For DOS & Windows 3.Xi Uživatelský manuál Strana 36