Hi everyone,
I am planning to use my Nano 33 BLE with an external USB interface. Not using the on board micro USB. I am planning to use the FT232RL usb to serial interface IC. As I am familiar with this one as it was used in the old Nano.
My external USB VBUS pin will be connected to the VBUS pin on the Arduino and the solder joint made on the backside of the Arduino.
My external USB GND connected to one of the external ground pins.
My external USB D+ to the FT232RL
My external USB D- to the FT232RL
The FT232RL Tx and Rx to the external Arduino Tx and Rx pins.
The main question is about this last connection FT232RL to Tx and Rx can I simply connect them or are the Tx and Rx pins (37 and 38) of the NINA-B3X IC on the Nano 33 BLE? Or do I have to add some components here to step down from 5V to 3.3V? If so please share your ideas and schematic pictures on how to do this!
The main question is about this last connection FT232RL to Tx and Rx can I simply connect them or are the Tx and Rx pins (37 and 38) of the NINA-B3X IC on the Nano 33 BLE? Or do I have to add some components here to step down from 5V to 3.3V?
The nrf52840 is not 5V tolerant, you probably destroy it if you connect the 5V signals directly.
I am planning to use my Nano 33 BLE with an external USB interface. Not using the on board micro USB. I am planning to use the FT232RL usb to serial interface IC. As I am familiar with this one as it was used in the old Nano.
Excuse me but this sound quite silly. The nrf52840 has internal USB support, so you have direct control over the interface. If you connect your external FTDI chip to the serial interface you cannot upload sketches by that connection!
Thanks for your answer pylon!
I will elaborate a little
pylon:
The nrf52840 is not 5V tolerant, you probably destroy it if you connect the 5V signals directly.
On the official schematic however I see nothing else than a simple connection between D+ and D- of the micro USB port and the NINA B3X IC...
I have seen the numerous notices: Please note: Arduino Nano 33 BLE only supports 3.3V I/Os and is NOT 5V tolerant so please make sure you are not directly connecting 5V signals to this board or it will be damaged. Also, as opposed to Arduino Nano boards that support 5V operation, the 5V pin does NOT supply voltage but is rather connected, through a jumper, to the USB power input.
However I was challenged myself to explain this connection.
pylon:
Excuse me but this sound quite silly. The nrf52840 has internal USB support, so you have direct control over the interface. If you connect your external FTDI chip to the serial interface you cannot upload sketches by that connection!
I will explain myself here, I am developing a pcb shield for the Arduino, I however I want to solder the castellated edges directly on my shield for a lower profile. I do not plan to remove the Arduino so I am happy to make this sacrifice for a lower profile. When doing this I am afraid that I will be unable to plug in a USB plug into the Arduino's micro USB port as the shield's pcb will be directly under it. Therefor I wanted to move the connection and thereby adding another USB interface to the edge of my shield. I intend to use USB type C (usb 2.0 speed) anyways another reason for me to add another USB interface.
Why would I not be able to program the Nano 33 BLE through the Tx Rx pin? To my knowledge this is how the old Nano was programmed.
I have noticed the little D+ and D- pads on the bottom of the board. However I am not sure how I should be connecting to them (and if that is possible at all or the intended use case of these pads)
On the official schematic however I see nothing else than a simple connection between D+ and D- of the micro USB port and the NINA B3X IC...
That's the USB port, something completely different.
Why would I not be able to program the Nano 33 BLE through the Tx Rx pin? To my knowledge this is how the old Nano was programmed.
Yes, but the old Nano had an ATmega328p MCU which does not contain an internal USB port so the serial interface had to be sacrificed for the uploads. The bootloader of the Nano 33 BLE does no accept new sketches on the UART interface, it does that solely on the USB connector.
I intend to use USB type C (usb 2.0 speed) anyways another reason for me to add another USB interface.
The SAMD21 has a full speed USB 2.0 interface (although full speed USB 2.0 means only 12 Mbit/s).
When doing this I am afraid that I will be unable to plug in a USB plug into the Arduino's micro USB port as the shield's pcb will be directly under it.
Why not placing the Nano 33 BLE at the edge of the PBC so that the USB port is still accessible?