Nowadays USB port is used widely for data transactions between electronic devices and computers. In many scenarios, there is no need to communicate with the USB port directly, therefore electronic designers use USB to UART (RS232-Serial) converter chips, so the USB port is converted to a virtual COM port on the computer. The initial thought of many designers is to use FTDI chips to do the USB to UART conversion. There is nothing wrong with FTDI chips, however, they are expensive. In this article/video, I introduced a cheap USB to UART converter module that uses the MCP2200 chip from Microchip. The converter supports both 3.3V and 5V serial logic levels and uses three LED indicators for power connection, data transmission, and data reception.
The module supports the serial CTS and RTS pins, also six GPIOs that can be used for direct controlling of connected devices. The serial data of the module has been examined and decoded using the UART decoding feature of the Siglent SDS2102X Plus oscilloscope. So let’s get started!
Looks like both have enough pins to be installable as a module, the fine pitch of the pins can be difficult to handplace for reflow soldering (we gave up on that, and just use the module, here is an example
Nice board! I'd use miniUSB as well because it's sturdier than microUSB. FTDI is expensive because it supports up to 3MBaud rate, full modem signaling, besides CTS/RTS, it has DTR/DSR, RI, etc. Also has GPIO pins. I've used FT232RL for a number of years on my boards and have recently started to switch over to FT231X, which is at the same price point as the MCP2200 but full signaling in case I need it (not really) and 3MBaud rate, 512 bytes RX and 512 byes of TX buffers. Crystals are integrated. There's also EEPROM integrated to hold an ID that you can set with FT_PROG so your computer can recognize it and only open the correct port according to that ID
I use FT at up to 2MBaud to program ESP32 and 1MBaud for other things. Many other ICs can support TTL but for up to 115200 baud.
CR, maybe try placing the IC with both hands. The tweezers-holding hand exerts an upward force and the other hand presses down, both slightly, and you have better control of where the part goes, check and balance, not single-hand. Young people have an advantage over us but my trick has been working (until it no longer works :D)
We gave placing FTDI parts on the initial '1284P boards we made,
and that was enough of that! Buying a complete module with all the other components was basically a wash vs high risk of a failed reflow and time spent reworking trying to get them working.
Might go better these days with metal stencils, vs the mylar stencils that were available 10 years ago.
Yes, stainless steel stencils help quite a bit. With plastic stencil, the paste gets under the stencil's holes and smudges up the footprints after 2-3 boards. With SS every board is as good as the next. I used to rework up to 50% of my boards, in batches of 9-12 (small boards) but now I only have a few jumpers. I use SAC305 lead-free paste. It's nice. A lot less jumpers than lead paste. JLCPCB.com has SS stencils for $7. OSHstencils also has that but more expensive and usually not flat.
