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

Chapter 5

Programming Considerations

This chapter explains important considerations for programming the GPIB-SBX.

Initialization

On power up (pon), the CPU issues a bus reset by driving the reset drive, which generates the
RESET pulse on the GPIB-SBX.
The assertion of the RESET line resets the NEC µPD7210 TLC integrated circuit 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 Register A (AUXRA), Auxiliary Register B (AUXRB), and
Auxiliary Register E (AUXRE) are cleared.
• The Parallel Poll Flag and Request System Control (rsc) local message are cleared.
• The Internal Count Register (ICR) is set to a count of eight.
• The Transmit/Receive Mode 0 (TRM0) and Transmit/Receive Mode 1 (TRM1) bits in the
Address Mode Register (ADMR) are cleared.
All other register contents should be considered as undefined while the RESET line is asserted
and after the RESET line has been cleared. All Auxiliary Mode Register (AUXMR) commands
are cleared and cannot be executed. All other GPIB-SBX registers can be programmed while the
GPIB-SBX internal signal pon is set. When pon is released or cleared (by issuing an immediate
execute pon auxiliary command to the GPIB-SBX), the interface functions are released from the
pon state and the auxiliary commands can be executed.
A typical programming initialization sequence for the GPIB-SBX might include the following
steps:
1. Write the Chip Reset command to the AUXMR to place the GPIB-SBX in a known quiescent
state.
2. Set or clear the desired Interrupt Enable bits in the Interrupt Mask Register 1 (IMR1) and the
Interrupt Mask Register 2 (IMR2).
3. Load the GPIB-SBX primary GPIB address in the Address Register 0 (ADR0) and the
Address Register 1 (ADR1).
© National Instruments Corporation 5-1 GPIB-SBX User Manual