Explaining DACKN When Using TNT4882 GPIB Controller Chip Hardware: GPIB
Problem: What does the command DACKN do? When DMA asserts DACKN, does this enable the FIFO register access irrespective of the ADDR(4..0) and the CSN=Unasserted? That is, is asserting DACKN, ABUSN, and BBUSN all that is required from DMA to address the TNT 4882 GPIB Controller Chip? Does WRN/RDN strobe the data?Solution: Asserting DACKN always selects the FIFOs. ADDR4:0 and CSN are ignored, while DACKN is asserted. When using 8-bit DMA, you must use data bus B (D15:8). So, you should assert DACKN and BBUSN and unassert ABUSN.Refer to the Hardware Considerations: Generic Pin Configuration chapter in the TNT4882 Programmer Reference Manual in the related links section for more information. Related Links: TNT4882 Evaluation Board Installation Guide and Specifications Attachments:
Report Date: 06/20/1997 Last Updated: 04/03/2008 Document ID: 0YJ81SVD |
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