For example, for the HP 75000 Series C Mainframe with an HP E1406 Command Module, VXI A16 address space starts at 1F0000h (h = HEX). In the HP E1406 Command Module, the A16 space is divided so modules are addressed only at locations beginning with C000h within A16. Each module is allocated 64 register addresses (40h). The module base address is related to the logical address set by the logical address switch on the module:

base address (h) = (logical addressh)*40h + C000h

For the HP E1459A, the factory-set logical address is 144 (90h), so to address the Status/Control register of an HP E1459A using the HP E1406 Command Module:

base address = (90h)*(40h) + C000h> = E400h

register address = [A16 location]h + [base addr]h + [register offset]h register address = 1F0000h + E400h + 04h = 1FE404h

Register Definitions

The following registers can be accessed on the HP E1459A:

•ID Register (base + 00h)

•Device Type Register (base + 02h)

•Status/Control Register (base + 04h)

•Edge Interrupt Status Register (base + 06h)

•Data Available Status Register (base + 08h)

•Watchdog Timer Control/Status Register (base + 0Ah)

•Command Register of Port 0/2 (base + 10h)

•Channel Data Register of Port 0/2 (base + 12h)

•Positive Edge Detect Register of Port 0/2 (base + 14h)

•Negative Edge Detect Register of Port 0/2 (base + 16h)

•Positive Mask Register of Port 0/2 (base + 18h)

•Negative Mask Register of Port 0/2 (base + 1Ah)

•Debounce Clock Control/Status Register of Port 0 and 1/Port 2 and 3 (base + 1Eh)

•Command Register of Port 1/3 (base + 20h)

•Channel Data Register of Port 1/3 (base + 22h)

•Positive Edge Detect Register of Port 1/3 (base + 24h)

•Negative Edge Detect Register of Port 1/3 (base + 26h)

•Positive Mask Register of Port 1/3 (base + 28h)

•Negative Mask Register of Port 1/3 (base + 2Ah)

•Debounce Clock Control/Status Register of Port 0 and 1/Port 2 and 3 (base + 2Eh)

HP E1459A Register Definitions 77