Programming Considerations; Initialization - National Instruments GPIB-1014 User Manual

Chapter 5

Programming Considerations

This chapter explains the initialization process, sending/receiving messages, and the
serial/parallel poll process. Additional information on programming the µPD7210 GPIB
interface chip can be obtained from the µ PD7210 GPIB-IFC User Manual by NEC Electronics
U.S.A., Inc. More specific information on programming the 68450 DMAC chip can be obtained
from Hitachi and Motorola technical data.

Initialization

On power-up, the VMEbus system typically issues a system reset (SYSRESET*) that drives the
GPIB-1014 RESET* signal active. This action clears both Configuration Registers and
initializes the following circuitry:
• Timing State Machine
• DMA Gating and Control
• GPIB Synchronization and Interrupt Control
• Interrupter
• DTB Requester
µPD7210 TLC
•
• 68450 DMAC
The GPIB-1014 also has another method for initializing the circuitry on the card. If the Local
Master Reset (LMR) bit in Configuration Register 2 is set, the RESET signal is driven and the
GPIB-1014 is initialized in the same manner.
The NEC µPD7210 Talker/Listener/Controller (TLC) integrated circuit is initialized as follows:
• The local message pon is set and the interface functions are placed in their idle states (SIDS,
AIDS, TIDS, SPIS, TPIS, LIDS, LPIS, NPRS, LOCS, PPIS, PUCS, CIDS, SRIS, SIIS).
• All bits of the Serial Poll Mode Register (SPMR) are cleared.
• The End Or Identify (EOI) bit is cleared.
• All bits of the Auxiliary Registers A, B, and E (AUXRA, AUXRB, and AUXRE) are cleared.
• The Parallel Poll Flag and Request System Control (RSC) local message are cleared.
• The Internal Clock Register (ICR) is set to a count of eight.
© National Instruments Corporation 5-1 GPIB-1014 User Manual