Hi all,
I'm currently using, MQX 4.0, PXS2010 and RS-485 transceiver (SP485EE). (my board, not the tower)
I'm using the example rs485.c with hardware flow control:
rs485_dev = fopen (RS485_CHANNEL, (const char *) IO_SERIAL_HW_485_FLOW_CONTROL);
twr-pxs2010 connects GPIO[51] -> DE, GPIO [12] -> RE.
my board connects GPIO[98] -> DE, GPIO [99] -> RE.
My question is how to change these pins in the MQX, to work with DE / RE automatically?
Thanks in advance,
Eddie
Solved! Go to Solution.
Hello,
PXS20 LinFlex module doesn't implement hardware signal for RS-485 transceiver DE (Driver Output Enable). It has only TXD and RXD signals.
IO_SERIAL_HW_485_FLOW_CONTROL open flag is not supported on MQX 4.0 PXS20 BSP, and thus the DE signal would need to be implemented using a GPIO output and user software. MQX I/O User's Guide describes the steps for this in chapter 5.11.
Hello,
PXS20 LinFlex module doesn't implement hardware signal for RS-485 transceiver DE (Driver Output Enable). It has only TXD and RXD signals.
IO_SERIAL_HW_485_FLOW_CONTROL open flag is not supported on MQX 4.0 PXS20 BSP, and thus the DE signal would need to be implemented using a GPIO output and user software. MQX I/O User's Guide describes the steps for this in chapter 5.11.
Hi Martin,
Thank you for answering me!, I will implement DE signal by software.
Hello
Where do I do I find if a processor supports the IO_SERIAL_HW_485_FLOW_CONTROL? I will be using a I20 processor. MK20DN512VLK10.
UART module on Kinetis parts has support for RS-485 in hardware (there is dedicated transmitter RTS output signal for this).
If there is hardware support in the module, IO_SERIAL_HW_485_FLOW_CONTROL open flag is supported in MQX serial driver.
On Kinetis, if we open serial device with IO_SERIAL_HW_485_FLOW_CONTROL flag, the driver will enable RTS signal in the port control module, and it will also configure UART module MODEM register for this functionality.
Thanks for help. Freescale does some very good things. Just connecting all the dots takes some work.