I want this development board. (which is not yet)

[AVI-crak]

Your mockups have a weird property to grow in value. I think this is due to the huge number of electronic components on the PCB, literally for all occasions. It is good for study, and completely useless for use in real life. That is, after debugging the program on the prototyping board of your production, the user must independently design the printed circuit board for the requirements of his project. It requires higher skills than you think. That is, at this stage, a huge stratum of lovers falls off to wind one board to another with the help of scotch tape, and so that it then works. (figurative expression).

Almost all stop on the breadboard with ali express on the 103 series chip.

In order for the user to be able to use your debug board in a "ready-made" device of its own manufacture, your debugging must be super cheap. This means using components without which work is impossible + these components must be complex.

Minimum option:

+ STM32F469NG,

+ fast qspi memory in a WNG008 package

+ sdram 32 bits in CSP BGA package

+ compact panel for installing an SD card

+ compact quartz resonators

+ connector for a cheap display with DSI interface, for example from Y330

+ connector for touch glass - compatible with the display

+ AD9288BSTZ-100 installation site with simple logic for converting a parallel interface to DDR (4 + 4) with connection to qspi bus

+ dual current amplifier for AD9288BSTZ-100 ad8034 or free space for it

+ minimal set of modern pulse stabilizers 3.3v + 1.2v + linear arj for the ADD line - from 5v input

+ place for the connector with a 2.54mm pitch, and a duplicate on the edge of the board like the ESP8266 (it looks that way)

After all this wealth, there are about 80 free contacts left - this is enough for creativity. The dimensions of the printed circuit board are approximately 60 * 60mm. It does not make sense to solder all components on a breadboard - but the display and the sensor must be included. Price: here I am lost, maybe you tell her yourself.

And yes, the programmer is not needed, everyone already has it.

Advantages - this debug board will be bought not only for entertainment, but also for the manufacture of its devices. That is, they will buy more than one piece per person - after all, this is exactly what you lack!

Display Contacts:

[AVI-crak]

At the expense of converting a parallel bus of 8 bits to 4 bits DDR format - for use with the qspi interface.

I checked - it is real.

I used ad9283brsz-100 and fine logic sn74lvc541, sn74lvc244, and a little more 74lvc logic in the sot23-5 package. I managed to save the digitized signal with a sampling rate of 100 MHz. I used only one channel qspi, because for the case lqfp208 it would not work otherwise - contact pads are too scattered. At such frequencies, the influence of incorrectly designed tracks on a printed circuit board becomes fatal.

In case of using AD9288BSTZ-100 - it is necessary to use two qspi interfaces. In this case, the digitization rate will be about 200 MHz.

For DMA, this means block logging timings of 4 * 32bit + 12 cycles for the bus arbiter. Is quite real.

First we knock down, and then we kick our feet. (anecdote from an ant about hunting for elephants)

[AVI-crak]

About the display.

I could find the cheapest option of the available 4 inches on Ali Express. This means that you may be able to find a cheaper offer. In any case, it does not make sense to use exotic options. It is necessary to use what is available in large quantities. Documentation on the display, as well as its modes of operation - all this can be found in the public domain. In the picture there are tips.

[AVI-crak]

RAM in the CSP BGA package is much cheaper than outdated analogues. Cheaper for the chip maker, and for you as buyers. But the trouble is that you need to buy a lot, more than 10,000 pieces.

For the production of a single instance of a multilayer printed circuit board - the price is overpriced. However, in a batch of more than 200 pieces - the price drops to an acceptable level. And yet, you already know that.