How to disable UART communication(ttyS0)

Technical Support
#1

@superceleron
@goenjoy
@zonggestsu
@numbqq
@Frank

Hi
How can I change my baud rate(115200 to 9600) and disable console for uart ttyS0 in android pie in VIM3L board.

#2

Hello @Pradeep_Kumar_Upadhy

ttyS0 is the default debug uart, why you want to disable it?

#3

Hi,
I want to use as uart this port where i want to connect usb to uart and communication between that.

ttyS0 is make stack on the boot
#4

Hello @Pradeep_Kumar_Upadhy

@goenjoy will help you with this issue.

#5 
xiong@server:/users/xiong/work/amlogic/vim3/vim3_64bit/common$ git diff
diff --git a/arch/arm64/configs/kvim_defconfig b/arch/arm64/configs/kvim_defconfig
index eb29ec5f0cb8..52efb9952609 100644
--- a/arch/arm64/configs/kvim_defconfig
+++ b/arch/arm64/configs/kvim_defconfig
@@ -195,7 +195,7 @@ CONFIG_AMLOGIC_CPUFREQ=y
 CONFIG_AMLOGIC_MESON_CPUFREQ=y
 CONFIG_AMLOGIC_INPUT_BOOST=y
 CONFIG_AMLOGIC_UART=y
-CONFIG_AMLOGIC_SERIAL_MESON_CONSOLE=y
+CONFIG_AMLOGIC_SERIAL_MESON_CONSOLE=n
 CONFIG_AMLOGIC_IOMAP=y
 CONFIG_AMLOGIC_PINCTRL=y
 CONFIG_AMLOGIC_PINCTRL_MESON_GXL=y

Set CONFIG_AMLOGIC_SERIAL_MESON_CONSOLE to n to disable the serial port

#6

Hi @goenjoy and @xiong.zhang
I have try this but still it’s coming as console ttyS0(pin 20,19,18,17) and when i am connecting gps module with this uart it stuck on the khadas image even it’s not going to bootloader.

#7

@Pradeep_Kumar_Upadhy

xiong@server:/users/xiong/work/amlogic/vim3/vim3_64bit/common$ git diff
diff --git a/arch/arm64/boot/dts/amlogic/kvim3l.dts b/arch/arm64/boot/dts/amlogic/kvim3l.dts
index da7c50d22e85..81f2a901fcf0 100755
--- a/arch/arm64/boot/dts/amlogic/kvim3l.dts
+++ b/arch/arm64/boot/dts/amlogic/kvim3l.dts
@@ -1568,11 +1568,11 @@
 };
 
 &uart_A {
-       status = "okay";
+       status = "disabled";
 };
 
 &uart_C {
-    status = "okay";
+    status = "disabled";
 };
 
 &saradc {

Try to set uart_A and uart_C to disabled state

#8

Hi @xiong.zhang

I have try this but it’s not working. When i am sending anything like “byte code running” at the time of the boot loading that time it’s stuck and showing

vpp: Rx hdr_info.hdr_sup_eotf_smpte_st_2084 = 0
normal power on
boot wol: disable
saradc: 0x28a, hw_ver: 0x32 (VIM3.V12)
syntax error

gpio: pin GPIOAO_7 (gpio 7) value is 1
port mode is usb3.0
Command: bcb uboot-command
Start read misc partition datas!
BCB hasn’t any datas,exit!
syntax error

Hit Enter or space or Ctrl+C key to stop autoboot – : 1 … 0
kvim3l# code running