What happened to those Arduino Nano boards? I liked them the most because they had only three LEDs (the same LED was for RX and TX), micro USB, had 10 pin CH340E USB to serial chip, were single-sided, were designed fot both TQFP and VQFN ATmega328s and were green.
I bought quite a few of those during a few years when they were available for $1.38 with free shipping but now I couldn't find any place selling them anymore :-/ I did find a dozen of places where those boards are still listed but they are out of stock at avery single place I found them.
Yes, the PCBs are of course double-sided, what I wanted to say is electronic components are on one side of that board only. I really like that.
I've spent a few hours yesterday and a few hours today searching for that very version of Arduino Nano but I didn't find any. There was another almost identical version of that board with just minor changes around voltage regulator but I could't find that one either.
There are similar designs with all components on one side but the microcontroller is not ATmega328.
Before starting designing the PCB I wanted to check if somebody already did that.
CH340E doesn't have DTR pin and I think they used TNOW pin (which is not present on all other variants of CH340) for controlling the LED which is for both RX and TX.
I might desing similar PCB without ISP connector and instead of the traces for micro USB port I might design contacts for micro USB breakout PCB because I have about 20 of those.
I don't need ISP header because for ISP programming I am using iProg+ where I can quickly connect MISO, MOSI, SCK and RST directly on µC pins or to the header.
Clones are available from China. Probably a couple of manufacturers and dozens of vendors. As always, have some test code ready to test them during the complaint window.
As I said, I've spent 2 times several hours searching for that particular version of the PCB but I could't find it. I checked every single Arduino Nano PCB from Aliexpress and I can assure you they don't have them anymore.
I did 184 orders from Aliexpress with approximately 10 items per order in the last six years and I can check in the history from where I bought those very PCBs.
For example, I've bought some of those PCBs many times from exactly these links:
You are right. In looking at it again all the single side component one seem to be from the same manufacturer and use a LGT8F328P chip, which is sort of compatible with the ATmega328P chip.
Yes, if those LGT8F328P based boards had tiny CH340E I'd buy them and replace the microcontrollers or I might even use them as they are. I got used to that small CH340E and I don't like boards with bigger variants of USB to serial ICs.
I might buy a few LGT8F328P anyway, just to test DAC and differential amplifier with programmable gain. But I prefer the original ATmega328 because LGT8F328P has different programming pins and EEPROM works by emulating it. On the other hand, there are cases where it would be easier running the program at 32 MHz (for example when generating composite video signal) or using one more 16 bit timer with output up to 64 MHz.
