8 thoughts on “ 3 Ways to Use Arduino as USB Serial Adapter Converter ” Duinosoar 4th January 2019 at 8:29 pm. You could just program the Arduino with the default “empty” sketch (i.e. Empty setup() and loop() functions). Since all digital pins default to input mode after a reset, they will remain as input, since the empty sketch will not change the mode of the pins.
$begingroup$I have a TI86 calculator that I've had for over 7 years now. Well I'm letting a lady friend on mine borrow it, and I was going to load it up with some apps for her. And the tradeoff is happening this weekend. So I figured, 'hey, let's just build a cable really quick'. Well I got going down the rabbit hole and since I don't have a serial or parallel port anymore, I'd need a converter.
- Jul 14, 2011 Hello, I've been going through a lot of tutorials online on using an atmega8 for USB to TTL conversion instead of an FT232 which is a lot more expensive compared to just an atmega8.
- FT232RL USB to Serial UART (TTL) Adapter is a simple and inexpensive way to connect PIC, AVR or ATMEGA MCUs to a PC or Mac via USB connection. FT232RL is an impressive chip because it implements full v2.0 USB protocol, needs no external crystal, has integrated EEPROM for device ID and product description strings and comes with Royalty-Free driver.
So I found an AVR USB to Serial converter schematic (which I'm sure ya'll are really familiar with) here:
Couple things:
1. I don't have a straight ATMega84888 around. I only have the 48A-MUPU, 88A-MUPU, and the 324P-20PU (which is my favorite) and 328P-PU (Second favorite) immediately available. Without sounding too dumb, am I correct in assuming with the exception of the 324P, the other AVR's I have are compatible? I've used a 328P before for some stuff for the 88 since according to the datasheet it's more or less the same chip, just different grades of it.
2. I only have a 16 Mhz and 20 Mhz crystal. Would it be disastrous if I used those instead, or do I need to modify the code to be safe?
And then last question on this schematic:
- If I had 3.6V and 5.1V Zeners, could I make them work? Is there an alternative if not? Zeners aren't something I use, so they're also a mystery to me sometimes too.
So like I said, silly questions. But I'd rather ask before I go wasting my chips and parts, you know?
Gracias, my friends.
1 Answer
$begingroup$Yes, the various atmega parts are likely to be compatible for this particular application. V-USB does not use many internal resources.
V-USB supports both 16MHz and 20MHz crystals. You will have to modify the circuit.
Are you going to use this circuit with AVR? Because you AVR circuit produces TTL-level serial data (0/5v), while 'The Serial Link' circuit expects RS232-level serial data (-12/+12V). The serial link circuit uses all the zeners and resistors to convert RS232-level to a TTL-level in a special way.
Usb To Serial Driver
So the two schematics you have posted are not compatible, unless you add another level shifter / converter (MAX232) so you can go TTL->RS232->TTL, which seems silly to me.