receiving and sending data from arduino to stml476RG - c

Question

I am looking to receive serial data from an arduino, and then transmit the data received back to the arduino, however I am having trouble receiving the correct data. Below is my code, I am not sure on where I have gone wrong, can anyone see any problems?
I am using register level programming and using USART 3 on the STM32L476RG development board, an I am using ADM485 chip to transfer the data between each serial port.
#include "stm32L476XX.h"
#include "stdio.h"
int T ;
int R ;
uint8_t z;
void USART3_init(void)
{
USART3->BRR |= 26UL<<4; //BAUD RATE MANTISSA 234UL<<4
USART3->BRR |= 1UL<<0; // BAUD RATE FRACTION 6UL<<0
USART3->CR1 |= 1UL<<0; //enable USART
USART3->CR1 ^= 0UL<<28; //1 start bit, 8 data bits, n stop bit
USART3->CR1 ^= 0UL<<12; //also sets word length to 8 data bits
USART3->CR1 ^= 0UL<<10; //no parity control
USART3->CR1 |= 1UL<<6; //Transmission complete interrupt enabled
USART3->CR1 |= 1UL<<7; //TXE interrupt enable
USART3->CR1 |= 1UL<<5; //RXNEIE interrupt enable
USART3->CR2 ^=00UL<<12; //1 stop bit
USART3->CR1 |= 1UL<<3; // enable transmitter
USART3->CR1 |= 1UL<<2; // enable receiver
NVIC_EnableIRQ(USART3_IRQn); //enable USART interrupts
}
void Delay(void)
{
uint32_t i=0;
for (i=0; i<50000; i++){}
}
void USART3_IRQHandler(void)
{
//Delay();
if ((USART3->ISR>>5)&1UL) //Check if RXNE interrupt is high
{
z = USART3->RDR; //put what is on RDR into Z (also clears RXNE flag)
GPIOB->ODR |= 1UL<<5; //set transceiver into transmit mode USART3->TDR = z; // Clears TXIE flag and outputs z on TX
}
if ((USART3->ISR>>7)&1UL) //Check if TXIE interrupt is high
{
GPIOB->ODR &= 0UL<<5; //sets transceiver in receive mode
}
if ((USART3->ISR>>6)&1UL) //Check if TC interrupt is high
{
USART3->ICR |= 1UL<<6; //Clear TC flag
GPIOB->ODR &= 0UL<<5; //Set transceiver in receive mode
}
}
void RCC_GPIO_init(void)
{
RCC->APB1ENR1 |= 1UL<<18; //Enable USART 3 clock
RCC->AHB2ENR |= 1UL<<1; //Enable GPIOB clock
GPIOB->MODER = 0; //reset all register bits
GPIOB->MODER |= 2UL<<20; //enable GPIOB pin 10 as alternate function
GPIOB->MODER |= 2UL<<22; //enable GPIOB pin 11 as alternate function
GPIOB->MODER |= 1UL<<10; //enable GPIOB pin 5 as output
GPIOB->AFR[1] = 0; //reset all register bits
GPIOB->AFR[1] |= 7UL<<8; //enable GPIOB pin 10 as TX
GPIOB->AFR[1] |= 7UL<<12; //enable GPIOB pin 10 as RX
GPIOB->ODR ^= 0UL<<5; //GPIOB pin 5 as low (to put ADM485 transceiver in receive mode)
}
int main (void)
{
RCC_GPIO_init();
USART3_init();
while(1)
{
}
}