STM32 Oscilloscope

Features

Vertical (Voltage/Frequency)

• V/Div
• AC/DC
• Offset
• Invert
• Probe divider / multiplier

Horizontal (Time)

• T/Div
• Offset

Trigger

• Voltage level trigger
• Trigger on rising / falling edge
• Single trigger / force trigger / trigger continiously
• Auto detect and track trigger level
• Trigger at fixed frequency / Trigger output
• External trigger
• Pretrigger (sample continiously then stop n samples after the trigger)
• Filtered trigger (low frequency / high frequency / number of pulses)
• Video trigger
• RS-232 trigger

Auto Scale

• Voltage
• Period

Metered values

• Voltage
• True RMS
• Average
• Peak
• Peak to peak
• Frequency
• Duty

Markers

• Voltage
• t1
• t2
• delta t
• frequency

Data output

• Save display snapshot to picture
• Save display frames for movie
• Save wave data to file (raw / .CSV)
• Stream non interrupted wave data to file

Display modes

• Waveform

range (old oscilloscope method)

Average per sample

Average per waveform

• XYZ
• Fourier transform

Spectrum

Average spectrum

Subtract average

Spectrogram

• Turtle - Channel A = speed, Channel B = direction
• TV (pixel brightness)
• Histogram
• Roll mode (continuous scrolling)

BPM mode for heart rate monitoring

wide range of scroll rates

dynamically zoom in to check on activity of extremely slow rates

Protocol decoding

• RS-232
• TTL RS-232
• IR remotes
• I2C
• SPI

DSP

• Pre-scale before process
• Add channels
• Subtract channels
• Multiply channels
• AM demod
• FM demod
• Configurable bandpass filtering
• Phase tracking hum removal
• Audio output

Output and control interfaces

• Computer via RS232
• Computer via Wireless RS232
• LCD touch screen
• Computer via USB

Logic analyzer

• Multichannel

Coding

Limits

• The three A/D converters are 12 bits

Maximum guaranteed clock frequency is 14 MHz, giving 1 MHz sample rate

Maximum possible with a 8 MHz crystal is 12 MHz

Two ADCs can be run in interleave for (12 / 14) * 2 = 1.74 MHz (highest guaranteed sample rate)

Maximum ADC clock rate at 72 MHz system clock is 36 MHz giving (12 / 14) * 2 = 5.14 MHz

Maximum system clock is 128 MHz giving a theoretical maximum of 9.14 MHz by overclocking everything

• System memory is 64 KB

Protocol

One byte each:
C SS DDD...
C = Code
S = Size
D = Data

Commands PC → STM32

• 0 0 4 DDDD - Set sample rate in Hz
• 1 0 5 D DDDD - Trigger mode & voltage
• 2 0 1 D - Input type 0=DC, 1=AC, 3=frequency
• 3 0 4 DD.DD - Probe gain
• 4 0 1 D - A/D gain
• 5 0 1 D - Number of channels
• 6 0 2 DD - Set pin state of a 16 pin port
• 7 0 0 - Reset
• 8 0 4 AAAA - Read data from address
• 9 0 8 AAAA DDDD - Write data to address
• 10 0 4 AAAA - Execute address

Commands STM32 → PC

• 0 SS D D... - Sample data, 8 bit unsigned
• 1 SS HL HL... - Sample data, 8 bit unsigned, H = highest value during the sample period, L = lowest value during the sample period
• 2 SS DD DD... - Sample data, 16 bit per sample
• 3 SS DD DD... - Pin state from one 16 pin port
• 4 0 4 DDDD - Return data from address
• 5 0 0 - Ready

Advanced features for the future

• Realtime view and control over IP by another computer
• iPad/IPhone view and control
• Web interface
• VGA output