drivers: serial: ra: reduce uart baud rate error

Using the 8 base clock cycles per bit period setting (instead of 16) reduces the uart baud rate error when using a 12MHz crystal (found on many RA Microcontroller development kits boards). This setting also slightly reduces the error when using the internal 48MHz oscillator, used by the Arduino UNO R4 Minima board currently support by Zephyr. Signed-off-by: Ian Morris <[email protected]>
YoeDistro · Feb 5, 2024 · 826d67a · 826d67a
1 parent caacc27
commit 826d67a
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/drivers/serial/uart_renesas_ra.c b/drivers/serial/uart_renesas_ra.c
@@ -216,11 +216,11 @@ static void uart_ra_set_baudrate(const struct device *dev, uint32_t baud_rate)
 	uint8_t reg_val;
 
 	reg_val = uart_ra_read_8(dev, SEMR);
-	reg_val |= REG_MASK(SEMR_BGDM);
-	reg_val &= ~(REG_MASK(SEMR_BRME) | REG_MASK(SEMR_ABCSE) | REG_MASK(SEMR_ABCS));
+	reg_val |= (REG_MASK(SEMR_BGDM) | REG_MASK(SEMR_ABCS));
+	reg_val &= ~(REG_MASK(SEMR_BRME) | REG_MASK(SEMR_ABCSE));
 	uart_ra_write_8(dev, SEMR, reg_val);
 
-	reg_val = (data->clk_rate / (16 * data->current_config.baudrate)) - 1;
+	reg_val = (data->clk_rate / (8 * data->current_config.baudrate)) - 1;
 	uart_ra_write_8(dev, BRR, reg_val);
 }