UART

UART Library FAQ

1. UART Not Working After Initialization

Q: Nothing is transmitted or received.
A:

• Check CPU_CLK matches your crystal frequency (e.g., 11.0592MHz)
• Verify physical connections: TX → RX, RX → TX, and common GND

2. Garbage Characters Received

Q: The received data appears corrupted.
A:

• Ensure baud rate settings match on both devices (e.g., 9600 or 115200)
• Call UART_Init(115200) on both transmitter and receiver for 115200 baud

3. UART_SendString() Sends Incomplete Data

Q: Only part of the string appears on the receiver side.
A:

• Ensure your string ends with a null terminator

4. UART_ReceiveChar() Gets Stuck

Q: The receive function blocks indefinitely.
A:

• Check if the transmitting device is actually sending data
• Implement a timeout mechanism to avoid hanging

5. How to Receive Data Without Blocking?

Q: Can I check for data before calling receive?
A: Yes, use UART_DataAvailable() before reading:

6. Can I Change Baud Rate Later?

Q: Is dynamic baud rate switching possible?
A: Yes, simply call UART_Init(new_baud_rate) again with the new value.

7. Works at 9600 but Fails at 115200

Q: Higher baud rates cause data errors or nothing is received.
A:

• Use an 11.0592MHz crystal for accurate timing at high baud rates
• Keep UART wires short (less than 30cm recommended)