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Community Translation: PSoC™ CreatorでPSoC™ 4のUARTボーレートを変更 – KBA234803
The UART baud rate is determined by the clock that drives the SCB component, and depends on the clock divider value (clkDivider) calculated using Equation 1:
The following example demonstrates how to change the UART baud rate in run time. This example shows how to calculate and implement the clock divider value to achieve a target baud rate of 115,200 bps.
- Place a UART component in the top design (*.cysch) in the PSoC™ Creator project.
- Enable the clock (Clock_1) as shown in Figure 1:
Figure 1 *.cysch component
- Make the following settings in the UART component configuration for this example. See Figure 2:
Figure 2 UART component configuration
- HFCLK (high-speed clock): 24 MHz
- Oversample: 13
- Target baud rate: 115,200 bps
4.Calculate the clock divider value using Equation 1. In this case, the divider value is calculated as 16.
5.Use the calculated value minus one (16–1 in this case) in the API to configure the clock as shown in the code snippet in the main.c file:
Clock_1_SetFractionalDividerRegister(15,0); //UART baud rate 115200 16-1
Code Listing 1/* Start SCB (UART mode) operation */
Clock_1_Stop();
if(uartboaudrate115200)
{
Clock_1_SetFractionalDividerRegister(15,0); //UART baud rate 115200 16-1
}
else
{
if(uartboaudrate9600)
{
Clock_1_SetFractionalDividerRegister(199,0); //UART baud rate 9600 200-1
}
}
Clock_1_Start();
UART_Start();
while(1)
{
UART_UartPutString("This is SCB_UartComm custom baudrate example project\r\n");
UART_UartPutString("\r\n");
CyDelay(500);
}Figure 3 shows the test result:
Figure 3 Test result
