Can't get the Read Example to work on ESP32 Arduino in PlatformIO about esp_dmx

[jonasprobst]

By the way, I'm using UART Port1 and GPIO Pins 16, 17 and 21 (standard ESP32) according to their DMX library example code:

... // lines 28 - 30
int enablePin = 21;		//dafault on ESP32
int rxPin = 16;
int txPin = 17;
...

Just realised, after studying those products for hours, that there is a discrepancy in the documentation: In their DMX library (above) they'r using GPIO21 as Enable. But if I map the the Sparkfun DMX Shield documentation to the Sparkfun ESP32 Thing Plus graphical datasheet it looks like Enable is GPIO4. I will ring the board through with my multimeter later today to rule out that it's a hardware / pin definition issue.

[jonasprobst]

Goodness, this has cost me soooooo much time :-S
The actual pins used on the Sparkfun DMX Shield for DMX communication via UART Port1 are:

// SparkFun DMX-To-LED Shield (https://www.sparkfun.com/products/15110)
constexpr gpio_num_t DMX_ENABLE = GPIO_NUM_4; // Output Enable (DE) of MAX3485. High for TX. [Pin 16]
constexpr gpio_num_t DMX_RX = GPIO_NUM_16;     // UART2 RX [Pin 15]
constexpr gpio_num_t DMX_TX = GPIO_NUM_17;     // UART2 TX [Pin 14]

and not GPIO21 as their DMX library and example code suggests.

[someweisguy]

Thanks for the kind words and so sorry for the confusion! I am also a bit perplexed - I have a couple Sparkfun DMX shields as well and I've had no issues using GPIO 21 as the enable pin. I do not see a revision number listed on my Sparkfun DMX shields. If your has a revision number on it, then I suppose that would be the issue.

Two quick side notes:

1. If you are using RDM with the Sparkfun shield you should solder a 120ohm resistor as the terminating resistor if you haven't already. Using RDM without that terminating resistor may cause problems sending and receiving RDM requests.
2. Based on the issue you submitted in #78, it appears you are using the latest commit which is currently experimental. You may continue to have issues using the experimental commit, but hopefully they are few and far between. If you would like to use a more stable commit, you should use the tagged commits. That said, I am very nearly done with version 3.1 so hopefully you'll have a stable version with the latest features soon!

Let me know if you have any comments, questions, or concerns!