Hantek DDS-3X25

The Hantek DDS-3X25 is a 25MHz PC-based function generator. It has no external controls, requiring a USB connection to a computer.

Hardware

TODO.

Configures the device. The payload is 6 bytes:

Byte	Bit	Description
1		Mode
	7
	6
	5	1 = Reset external trigger (send only once)
	4	1 = External trigger mode enabled
	3	External trigger: 0 = falling, 1 = rising
	2	0 = continuous, 1 = single wave
	1	Counter reset: 0 = leave, 1 = reset
	0	Measurement: 0 = frequency, 1 = counter
2
	7
	6
	5
	4
	3
	2
	1
	0	Output: 0 = pattern generator, 1 = programmable output
3		Digital I/O pins, bits 0-7
4		Bits 0-3 = digital I/O pins bits 8-11, bits 4-7 unused
5		Clock divider, based on 48KHz clock
6

THe response is 10 bytes:

the first 2 bytes are always 0
in frequency measurement mode:
- four bytes for the current frequency measurement, in network order. Multiply by 2 to get the actual frequency readout.
- four bytes for a "tick counter" in network order. This has the number of ticks per second, and is used to derive the frequency. Assuming a 100Mhz clock, this counter differs up to 4.17% at 8Mhz from the derived frequency -- investigate.
in counter mode:
- four bytes for the current counter, in network order.
- four bytes denoting the smoothed out frequency, identical to the first four bytes in frequency measurement mode.

When setting "close output power on", i.e. save configuration to memory: