Smaller MCU drive piezo

[avikde]

Related to #53

• blink
• debugging setup
• millis
• cmake build setup and separate app dir
• printf using UART
• comms with BOS1901

Trying a couple of dev kits

[avikde]

trying to read 0x4: get

• 0x42, 0xa0

should return https://cdn.shopify.com/s/files/1/0066/6628/9221/files/BOS1901CDS01.0.pdf?61

The default value of 0x4 is 0x2A0, i.e. this is working!

[avikde]

Reading 0x1a returns 0xc0 = {c0, 00}

• amplitude = 0
• full = 1, empty = 0

It is full since I have been sending bos1901rw(&bos, 0, 0), adding 0 to the FIFO.

[avikde]

Did the click on a power cycle too, so nothing is broken

After it stops, status = 0xE40

• FIFO_SPACE = 0
• empty = 1
• full = 0
• OVT = 0
• OVV = 1
• state = 0b11 = error

Lowering the voltage signal says RUN mode

f3f9a69 produced this signal on HV+

Comparing to the signal sent:

		for (int i = 0; i < 64; ++i)
		{
			bos1901rw(&bos, 0, 50*i);
		}

gets to ~32V, i.e. 1ct = 0.01V.

Frequency: the 64 counts took ~260us. With PLAY=00, should have been 1024 ksps = 1.024 Msps = 1.024 samples/us => 62.5 us for 64 samples. Off by a factor of 4?

[avikde]

Sine as of 01ad144

+/- since looks like this on OUT+ and OUT- (and difference)

[avikde]

• driving bimorph vs. this
• change frequency (changing PLAY seems to not be working?)
• reload waveform

Bimorph

The BIAS/SIG/GND method can send the entirety of the Vpp voltage to one of the piezos, whereas with this chip, will only get 95V. Other than that the performance should be similar. This one seems worse since one of the piezos is sitting at 0V for half the cycle.

But there is also an HV pin.