Going back to electronic after a 20 years break

The voltage management was designed by Jyetech to reflect the values they wanted to use. The resistors have the right values to form good voltage dividers, and as a result, converting between them and volt/div is pretty simple. It's not so simple for the timebase. Ideally, we'd like standard value, such as 10us/div, 50ms/div etc... Since we use 24 pixels per div, that would mean 10us/24, 50ms/24 etc... sampling frequency Unfortunately, we don't have the required  flexibility as far as sampling frequencies are concerned. Here is a  table of all the available values (prescaler x sampling time) 2 4 6 8 1,5 0,39 0,78 1,17 1,56 7,5 0,56 1,11 1,67 2,22 13,5 0,72 1,44 2,17 2,89 28,5 1,14 2,28 3,42 4,56 41,5 1,50 3,00 4,50 6,00 55,5 1,89 3,78 5,67 7,56 71,5 2,33 4,67 7,00 9,33 239,5 7,00 14,00 21,00 28,00 Time/sample (us) Multiple by 24, to get the time/div Not so great in terms of user exper

I tried several methods to redraw the waveforms as fast as possible, while keeping a high quality display. The target is ~ 30 fps, crystal clear. The underlying method is that we only draw vertical lines, not random lines. That way we maximize the setAddrWindow/push colors mode of the display controller. Method 1: That method is the dumbest: we clear the area to paint and redraw everything needed. Pros It is actually very fast, because the amount of data to paint is small compared to the display. Something like 5 to 10% Clearing an area with black is fast, just put 0 on the bus and toggle the write pin as much as needed. The speed is ~ ok (14ms) Cons It flickers a lot. It flickers because we actually draw the screen twice : once in black, once with the waveform. Method 2: Draw once To avoid the aforementioned flicker, the idea is to pre-calculate a column and send it. Pros It does not flicker at all (we only draw once). Cons  it is kind of slo

Very basic DMA-ADC capture test case with code derived from PigOScope  and signal coming from my El Cheapo signal generator . That's a promising start.

The DSO 150  input gain  is a 4 stages  circuit : G1 is driven by SENSEL3 (aka PA14) and enables switching between a gain of 10/11 (SENSEL3=1) and 10/1100 (SENSEL3=0) G2 gain is 2 G3 gain is driven by SENSEL0/1/2 (PA11/12/13) and can go from /1 to /40, more on that later G4 gain is (1+1000/150)=~ 7.7, additionally the signal is shifted by 1000/680 volt = 1.47 v The overall gain can vary from 10/11*2*1*7.7 => ~ x14 to 10/1100*2/40*7.7 => ~ /285  The SENSEL0..2 order is a bit weird : Gain       SENSEL0..2 GND           1 /1                4 /2                6 /4                7 /10              0 /20              5 /40              3 Ultimately the gain follows this table : SENSEL0..3                Gain 0                                    /71 1                                    GND 2                                    NC 3                                    /286 4                                    /7 5