Hi All,
The FTDI costs 2USD more than the ATmega16U2 but the atmel is has an external crsystal and is more faster with rx and tx data. No extra drivers needed when connecting it to pc with arduino installed. Then there are fake FTDI chips that get bricked when updating the drivers so as to prevent fake FTDI chips being used. Are there any more advantage using the ATmega16U2 ?
The UNO has two pairs of ICSP headers on its board, would it be necessary on a standalone board as well ?
One ICSP header is used to program the 16u2, you need it to load the FW and fix the FW if it gets corrupted somehow.
From posts on the forums, it seems like the 16u2 is more fragile electrically (how often does someone using a clone board report having damaged the CH340G or CP2102? I think I remember ONE post like that in the past 2 years. How often does someone report blowing the 16u2? A couple times a week). This makes me hesitant to use 16u2's as serial adapter in any design I might make. The CH340G is easy to handle as a part (SOIC-16 is easy to solder), easy to make custom boards for, and about 25 cents a pop; I think the pricing on CP2102 is similar.
I would never use an FT232, as I am not equipped to differentiate between real and fake units.
The FT232RL has an internal oscillator, instead of using an external crystal; this is an advantage in terms of reducing external component count.
Thank you just learning with experience.
So if they seem to be so problematic why would it be seen in an arduino when its been very popular for years. Would it possible to get an application schematic for the CH340G or CP2102 ?
Secondly do these 16U2 have to be programmed to be used as a USB to TTL connector ?
They are used for reasons not clear. Originally there was the idea that people would reprogram the 16u2 to make other kinds of USB devices (like you can do natively on a micro/leo); this wasn't promoted or made easy, though, so there are only a few projects that do this, (hoodloader, unojoy, etc), and they're not widely used. If this had been promoted and supported better, this could have been really cool, but 99+% of them stay programmed as a usb serial adapter :-/
See the datasheet for an application schematic; You can also reverse engineer an el-cheapo serial adapter from ebay (I used both as resources when I rolled my own CH340G serial adapter).
Yes, 16u2 is a general purpose microcontroller, it must be programmed to act as a USB-serial adapter.
I can't find the chip on Digikey, Mouser or Newark. Strange !!! but they are available on ebay and the only datasheet i could find was this
would the attached schematic be correct ignoring pins 9 -14 also.
are there any sketch available to upload to the 16U2 ?
found this from FTDI and that is just USD2.0 i guess this would be ok as the cost is low and does not require programming the chip.
Opted for this because the ATmege16 requires to be programmed and the FT232RL are priced at USD4. I would stick to the Atmel but the sketch to be uploaded is not easy to find.
