HP 8-Channel 196 kSa/sec Digitizer plus DSP E1433A manual HP E1433A VXI Device, Address Space

HP E1433A User's Guide

Module Description

The HP E1433A VXI Device

Address Space

The VXI system architecture defines two types of address space. A16 space consists of 64 KBytes and A24 consists of 16 MBytes.

The HP E1433A has a 32-bit port through which it has access to the A16 and A24 space. It can also use D32 to send and receive data though the port. Or it can use the port for 16-bit data transfers by using only 16 of the 32 bits available. The HP E1433A performs a different type of VME cycle depending on the number of bits transferred per cycle (two cycles for 16-bit transfers and one cycle for 32-bit).

Shared Memory

Shared memory provides a way for the HP E1433A to transfer data to a controller. The shared memory in the HP E1433A is mapped to the A24 VXI address space. The controller can then access that same address space to receive or write data. You can call a function to get the data. See the chapter on “The Host Interface Library.”

Memory Map

The following discussion of memory mapping is included for your information. You do not need it to operate the HP E1433A because this functionality is hidden when using the HP E1432A Host Interface Library software.

Refer to the HP E1433A block diagram (figure 5-1). The VXI interface maps some of the HP E1433A’s B-bus internal memory space so that it is visible to the VXI Bus. The port connecting the A and B busses also allows the VXI Bus access to the SRAM, DRAM, and inputs which are on the A bus. (SRAM stands for Static RAM; DRAM is Dynamic RAM.)

The VXI interface has two “windows” on the B bus memory space. Each is 512 K-bytes, which is 128 32-bit words. One of the windows is fixed and the other is movable. The movable window allows the VXI Bus access to many different parts of the memory space. The fixed window contains:

￿The A16 registers

￿The B-bus SRAM

￿The hardware registers

￿The FIFO (which is in DRAM)

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