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Line 69... |
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/**********************************************************************//**
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/**********************************************************************//**
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* Enable and configure UART.
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* Enable and configure UART.
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*
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*
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* @warning The 'UART_SIM_MODE' compiler flag will redirect all UART TX data to the simulation output. Use this for simulations only!
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* @warning The 'UART_SIM_MODE' compiler flag will configure UART for simulation mode: all UART TX data will be redirected to simulation output. Use this for simulations only!
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* @warning To enable simulation mode add <USER_FLAGS+=-DUART_SIM_MODE> when compiling.
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* @warning To enable simulation mode add <USER_FLAGS+=-DUART_SIM_MODE> when compiling.
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*
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*
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* @param[in] baudrate Targeted BAUD rate (e.g. 9600).
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* @param[in] baudrate Targeted BAUD rate (e.g. 9600).
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* @param[in] rx_irq Enable RX interrupt (data received) when 1.
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* @param[in] rx_irq Enable RX interrupt (data received) when 1.
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* @param[in] tx_irq Enable TX interrupt (transmission done) when 1.
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* @param[in] tx_irq Enable TX interrupt (transmission done) when 1.
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**************************************************************************/
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**************************************************************************/
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void neorv32_uart_setup(uint32_t baudrate, uint8_t rx_irq, uint8_t tx_irq) {
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void neorv32_uart_setup(uint32_t baudrate, uint8_t rx_irq, uint8_t tx_irq) {
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UART_CT = 0; // reset
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UART_CT = 0; // reset
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// raw baud rate prescaler
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uint32_t clock = SYSINFO_CLK;
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uint32_t clock = SYSINFO_CLK;
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uint16_t i = 0; // BAUD rate divisor
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uint16_t i = 0; // BAUD rate divisor
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uint8_t p = 0; // prsc = CLK/2
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uint8_t p = 0; // initial prsc = CLK/2
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// raw clock prescaler
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#ifdef __riscv_div
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// use div instructions
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i = (uint16_t)(clock / (2*baudrate));
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#else
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// division via repeated subtraction
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while (clock >= 2*baudrate) {
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while (clock >= 2*baudrate) {
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clock -= 2*baudrate;
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clock -= 2*baudrate;
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i++;
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i++;
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}
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}
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#endif
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// find clock prsc
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// find clock prsc
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while (i >= 0x0fff) {
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while (i >= 0x0fff) {
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if ((p == 2) || (p == 4))
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if ((p == 2) || (p == 4))
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i >>= 3;
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i >>= 3;
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