DMX driver mapped to D21G SERCOM
Hi,
I found this library for DMX: https://github.com/claudeheintz/LXSAMD21DMX
I have tried to use it on the D21G board as a DMX receiver. It compiles OK but I do not receive any data. The library is designed to use SERCOM4. If I understand the board description the RS458 interface is connected to Serial (that should be replaced by the DMX driver) using SERCOM1, but I'm not sure I have undertood how to do the mapping correctly. There is an instruction at the end of the header file that I tried to follow. The changes I have done is:
// +++ Test for SERCOM1
#define PIN_DMX_RX (0ul)
#define PIN_DMX_TX (1ul)
#define PAD_DMX_RX SERCOM_RX_PAD_3
#define PAD_DMX_TX UART_TX_PAD_2
// Set to PIO_SERCOM or PIO_SERCOM_ALT
#define MUX_DMX_RX PIO_SERCOM_ALT
#define MUX_DMX_TX PIO_SERCOM_ALT
// SERCOMn is pointer to memory address where SERCOM registers are located.
#define DMX_SERCOM SERCOM1
// sercomN is C++ wrapper for SERCOMn (passed to UART constructor)
#define DMX_sercom sercom1
Is this the correct settings for the RS485 interface or have I missed something?
Thank you Tom, great help! I used your settings and also had to remove the SERCOM3 handler in variant.cpp to avoid multiple definitions, then it compiles with no errors.
Now it works like a charm and DMX settings are received as expected, at least on channel one as I have tested so far.
BR Gunnar
Hi, the only setting you need to be aware of regarding the INDIO's RS485 is that the TXenablePin is on D9 and the serial port is called 'Serial' (D0/D1), see https://github.com/Industruino/libraries#rs485
The INDIO uses the MAX485 IC, which is compatible with the example used in the library https://github.com/claudeheintz/LXSAMD21DMX/blob/master/src/LXSAMD21DMX.h
Library >> INDIO
RX (5) >> RX (0)
(3) >> (9)
TX (4) >> TX (1)
I'm not an expert in pin mappings but my suggestion, based on the Industruino D21G pin mapping https://github.com/Industruino/IndustruinoSAMD/blob/master/variants/industruino_d21g/variant.cpp is you try this:
#define PIN_DMX_RX (0ul)
#define PIN_DMX_TX (1ul)
#define PAD_DMX_RX SERCOM_RX_PAD_3
#define PAD_DMX_TX UART_TX_PAD_2
// Set to PIO_SERCOM or PIO_SERCOM_ALT
#define MUX_DMX_RX PIO_SERCOM_ALT
#define MUX_DMX_TX PIO_SERCOM_ALT
// SERCOMn is pointer to memory address where SERCOM registers are located.
#define DMX_SERCOM SERCOM3
// sercomN is C++ wrapper for SERCOMn (passed to UART constructor)
#define DMX_sercom sercom3
and in .cpp you'd have to change
void SERCOM4_Handler() to void SERCOM3_Handler()
and in your sketch
SAMD21DMX.setDirectionPin(9);
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Asked: 6/21/18, 3:54 PM |
Seen: 2580 times |
Last updated: 6/22/18, 2:27 PM |