HP E1429A manual Register Programming Appendix C

4.Set the sample rate.

A. If the trigger source is not reference period / N (base + 4D16 bits 4 - 2 =1 0 0), the decade division register and binary division register must be set as follows:

write a value of 1 to base + 6116 write a value of 132 to base + 6316

B. If the trigger source is the reference period / N ( base + 4D16 bits 4 - 2 =1 0 0), then to set the sample rate (period) you must know the rate you want and the reference frequency. From these values, a value (N) is determined as shown below.

N = reference frequency / required sample rate

The reference frequency is then divided by N (Ref/N) to obtain the sample rate. N is represented by the decade division register (6116) and the binary division register (6316).

For example, to program a sample rate of 1 kHz (1 ms period) using the digitizer’s internal 20 MHz reference:

N = 20 MHz / 1 kHz = 20,000

1610 is written to the decade division register (base + 6116) to set a division by 10,000. All other bits are set to 0. 13210 is written to the binary division register (base + 6316) to set a division by 2. (Bits 7 - 4 must always be set to 1 0 0 0.) These settings divide the reference frequency by 20,000 which gives the required sample rate of 1 kHz.

5.Set the digitizer A/D converter as the high-speed clock source and data source for memory.

A.Using the traffic register (base +0216), set the pulse register as the high-speed clock source by setting bits 3 - 2 to ’0 0’. Retain the settings of the other bits.

B.Send a clock pulse to the internal high-speed bus by reading or writing (any value) to the pulse register (base +0816).

C.Using the traffic register (base +0216), set the A/D as the

high-speed clock source and as the high-speed data source by setting bits 3 - 0 to ’0 1 0 0’. Retain the settings of the other bits.

384 Register Programming Appendix C