AM6442: MCU UART bard rate

Tony Tang

Part Number: AM6442

Customer found the MCU UART baud rate is 2x as configured. for example set to 115200bps. on the PC side, need to set to 230400bps to communicate.

same setting to main domain UART, the baud rate is right.

over 1 year ago

0 Bin Liu over 1 year ago

TI__Guru*** 133096 points

Hi Tony,

Does the customer use Processor SDK Linux or MCU+ SDK? Which version?

0 Tony Tang over 1 year ago in reply to Bin Liu

TI__Mastermind 26086 points

Use Linux SDK 8.4

0 Bin Liu over 1 year ago in reply to Tony Tang

TI__Guru*** 133096 points

Tony,

Thanks. I will try to reproduce it next week and get back to you.

0 Bin Liu over 1 year ago in reply to Tony Tang

TI__Guru*** 133096 points

Hi Tony,

The following kernel will solve the issue:

diff --git a/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi b/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
index 09a668af9fd3..5e98f6035436 100644
--- a/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
@@ -12,7 +12,6 @@
                reg-shift = <2>;
                reg-io-width = <4>;
                interrupts = <GIC_SPI 185 IRQ_TYPE_LEVEL_HIGH>;
-               clock-frequency = <48000000>;
                current-speed = <115200>;
                power-domains = <&k3_pds 149 TI_SCI_PD_EXCLUSIVE>;
                clocks = <&k3_clks 149 0>;
@@ -25,7 +24,6 @@
                reg-shift = <2>;
                reg-io-width = <4>;
                interrupts = <GIC_SPI 186 IRQ_TYPE_LEVEL_HIGH>;
-               clock-frequency = <48000000>;
                current-speed = <115200>;
                power-domains = <&k3_pds 160 TI_SCI_PD_EXCLUSIVE>;
                clocks = <&k3_clks 160 0>;

0 Tony Tang over 1 year ago in reply to Bin Liu

TI__Mastermind 26086 points

Bin,

Thanks, So the reason is MCU UART module clock is 96MHz other than 48MHz?

0 Bin Liu over 1 year ago in reply to Tony Tang

TI__Guru*** 133096 points

Tony,

Yes it seems the SYSFW configures MCU UARTs in 96MHz. I am working with the sw dev team to resolve the issue properly.

Processors

Processors forum

AM6442: MCU UART bard rate