Is the SEN0628 8×8 serial protocol published anywhere?
Doug.Fajardo 2026-08-09 23:59:07 369 Views7 Replies I am trying to use the SEN0628 in Serial port mode. For a variety of reasons I can not use the DFRobot library (perhaps a separate subject).
When I connect 5v power, (The power light on the device is on), and look at the serial data lines with an oscilloscope (not connected to any processor), there is no data flowing (I was kinda hoping the device would just start running, but apparently not).
I suspect the device is waiting for some command(s) on the serial port to start working (e.g.: select 8x8mode?) - are these documented anywhere?
V1.3 is solid — no known issues.
Since you can't use the library and don't have USB, your best bet is to get the protocol from the source. Wire the SEN0628 to an Arduino Uno, run the official UART example, and sniff the TX/RX lines with a logic analyzer— the init handshake is short, maybe 10–20 bytes.
If that's not an option, post your processor model and why the library won't compile or run — someone here might have already solved the same porting issue.
Jason.Miao Jason - Thanks for the feedback; I guess I'll have to reverse-engineer it as you suggest (or possibly dissect the library).
FYI: My main issue is not compiling the library, its timing - calling the ‘get all data points’ method over I2c (running at 400 mhz) takes 22 milliseconds to complete on the ATmega 2560 - during which nothing else can run.
This ATmega is also driving stepper motors (and doing a few other things), and that much delay (at any single time) causes jerkiness in the motors.
My solution is to switch to the hardware-based serial port. The Arduino ‘hardware Serial driver’ uses interrupts on a char-by-char bases to collect data into a buffer; I can collect a lines of data into my 8x8 array with minimal processor overhead,
Yes, overall the serial port is slower, but this approach leaves the processor free for its other tasks with minimal interruption at any given time. The slower scan rate is not an issue - I only need around 2-5 scans/sec for my application.
22 ms of blocking I2C on an ATmega 2560 is an eternity when you're also pulsing steppers.The serial line might be slower in raw throughput, but non-blocking beats fast-and-blocking every time for motor control.
You can also check if the firmware has been burned in and if there are any issues with the update.
Jason.Miao I did update to firmware vers 1.3, and I haven't seen any notes suggesting a problem - has anyone seen such a comment? Thanks!
If you can't use the library,use USB-C instead — the module outputs 8×8 data automatically over USB at 115200 baud with no initialization needed.
Jason.Miao Yes, the USB works fine, - but my processor does not have a USB port available.
I was hoping to use the Serial data lines, as shown in the ‘8x8 example using UART’ example found at https://wiki.dfrobot.com/sen0628/docs/21559
