HP E1429A manual Data Register Offset

float a24offst;/* A24 offset from A16 offset register */

char rd_addr[80];/* command string variable */

/* Create the command string which reads the A24 base address from the offset register*/ sprintf(rd_addr, "DIAG:PEEK? %ld, %d", base_addr,16);

/* Send DIAG:PEEK? command */ IOOUTPUTS(CMD_MOD, rd_addr, strlen(rd_addr));

/* Read value from offset register */ IOENTER(CMD_MOD, &a24offst);

/* Multiply offset value by 256 for 24-bit address value */ a24offst *= 256.;

return (long)a24offst;

}

The Data Register Offset

Multiplying the value of the offset register (a24offst) by 256 (10016) converts the 16-bit register value to a 24-bit address.

The offset of the digitizer’s data register is 12 (0C 16). The offset is added to the A24 base address to form the complete register address:

0022000016 + 0C16 = 0022000C16

2,228,224 + 12 = 2,228,236

The offset of the data register can also be read with the SCPI command:

VINStrument[:CONFigure]:VME:SEND:ADDRess:DATA?

This command returns two values: A24,12. A24 indicates that the data register is in A24 address space and 12 is the offset of the data register.

150 Understanding the HP E1429 Digitizer Chapter 3