Is it possible to send/recieve on RS485 without flow control. I am working on stm32f4 platform with a MAX3160 multiprotocol transceiver(supports RS232 and RS485). The UART lines form STM32F4 are connected to the MAX3160. When the MAX3160 is configured to RS232 it works fine. But when configured to RS485(only 1 pin toggle on MAX3160, input/output lines are same) i am not able to send/receive data. The devices connected to RS485 are using modbus protocol. I am not using RTS/CTS and have configured NO\_FLOWCONTROL on UART. My modbus devices also has just 2 wires A+ and B-.

Could the RS485 data enable or not configuring CTS/RTS causing this issue.

I am not very experienced in hardware. So any pointers will help.

EDIT:
Yes. I am not too sure about the basics as this is the first time I am working on any hardware boards. I have a board with stm32f427. The USART1 lines are connected to a MAX3160 transreciever which supports both Rs232 and Rs 485, although not simultaneously. It can be configured with one pin. The input and output lines for both rs232 and Rs 485 are same. I connect the rx tx from these to the modbus device. I configure the uart with no flow control, 9600 baud rate, stopbit 1, no parity and enable Rs 232 pin on MAX3160. I use a rs232 to Rs 485 converter connector and connect the modbus device. It works fine. So i am sure the pi configuration is fine. Now I just enable pull the rs232/rs485 pin high to enable Rs 485. I remove the rs232 to Rs 485 converter and connect the modbus device directly. I am guessing it should work without any changes. But I hooked up a oasicalltor and I cannot detect anything. MAX3160 data sheet has some pin called DE485(data enable). Should this be set. Or some other change specific to Rs 485. Currently I have not set this data enable pin. If it needs to be set, when should it be set. My modbus device has only 2 wires A+ and B- which I have connected to Rx and Tx respectively.