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
已解决! 转到解答。
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.
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.