Sundance SMT118 - Manual (Page 18)

Version 1.0 Page 18 of 20 SMT118v2 User Manual
Read / Write to RS232
The following functions give an easy interface to the RS232 channels when
configured for simple Tx/Rx operation.
The following function is the basic UART register read routine. Supply the UART
number (0 to 3) and the register number (0 to 7).
#define uart_base 0xF9000000
int read_uart(int uart, int uart_reg)
{
int data;
data = read_global(uart_base + uart*8 + uart_reg);
return(data);
}
The following function is the basic UART register write routine. Supply the UART
number (0 to 3), the register number (0 to 7) and the required data.
write_uart(int uart, int uart_reg, int data)
{
write_global(uart_base + uart*8 + uart_reg, data);
}
The following function is the basic UART receive data routine. Supply the UART
number (0 to 3).
int rx_uart(int uart)
{
volatile int t;
// Wait for bit 0 of the UART status register to become set
// indicating that there is data in the receive FIFO.
while( ( (t=read_uart(uart, 5)) & 0x01) == 0 );
return(read_uart(uart, 0));
}