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communication between Titano and Grand Central
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communication between Titano and Grand Central

by rhoover on Sat Sep 26, 2020 7:18 pm

I am trying to use a PyPortal Titano for the UX on a project where it will pull input from the touchscreen and from Adafruit IO, then pass this data to a Grand Central Express which will use these inputs to set routines for a series stepper motor driven peristaltic pumps. This has seemed like a perfect hardware solution so far and I have made good progress on the individual elements of the project, working in CircuitPython. I have the Titano powered by the Grand Central over the I2C JST4 port. However, I cannot seem to communicate over I2C. Is it possible to set one of the boards as an I2C slave, or is this not doable on these M4 boards. If it is possible, how do I do this and find/set the requisite addresses? If I2C is not workable, what are the communication options on the Titano? The RX/TX pins are committed to the WiFi module and the SPI is talking to the TFT screen. Is there a good way to communicate by UART over the USB port?

Thanks!

rhoover
 
Posts: 3
Joined: Mon Sep 21, 2015 5:27 pm

Re: communication between Titano and Grand Central

by rhoover on Sun Sep 27, 2020 1:50 pm

Here is little update for those who may have the same question. The I2C pins in the JST-4 connector on the Titano, board.SDA and board.SCL, can be set up as TX and RX pins, respectively. This allows for UART communication between the boards, which will actually be better for this application and only requires moving two wires on the Grand Central board. The UART_Test_Script.py file is helpful for identifying possible TX and RX pins on any board. It can be downloaded here: https://learn.adafruit.com/pages/11671/elements/2985120/download

I think this resolves the issue for me, but I still welcome comments on this topic.

rhoover
 
Posts: 3
Joined: Mon Sep 21, 2015 5:27 pm

Re: communication between Titano and Grand Central

by aob003 on Wed Jul 21, 2021 3:33 am

Thanks for your post!

I've been trying to workout a similar problem, I need my pyportal to talk via LoRa, it appears the LoRA breakout boards are all SPI which isn't so convent, so I've reverted to using a Feather with LoRA modem and just trying to workout the best way to make the two controllers talk to each other.

I do have a bunch of devices on the I2C already, so if I change the mode of the JST-4 to UART I need to workout another way to talk to these sensors.

I'll let you know how I go.

Cheers.
Andrew.

aob003
 
Posts: 4
Joined: Tue Apr 13, 2021 11:15 pm

Please be positive and constructive with your questions and comments.