Linux/AM3352: About UART4 Issue

yimin bai34

Part Number: AM3352

Tool/software: Linux

Hi SIr

We followed the DTS setting to set UART4 and didn't measure the signal from TX pin

uart4_pins: pinmux_uart4_pins {
pinctrl-single,pins = <
AM33XX_IOPAD(0x968, PIN_INPUT_PULLUP | MUX_MODE1) /* UART0_CTSn.uart4_rxd */
AM33XX_IOPAD(0x96c, PIN_OUTPUT_PULLDOWN | MUX_MODE1) /* UART0_RTSn.uart4_txd */
>;
};

&uart4 {
pinctrl-names = "default";
pinctrl-0 = <&uart4_pins>;
status = "okay";
/* dmas = <&edma_xbar 32 0 9
&edma_xbar 33 0 10>;
dma-names = "tx", "rx";*/
};

please advise if there is any issue about the DTS setting

thanks

Yimin

over 7 years ago

0 Biser Gatchev-XID over 7 years ago

TI__Guru**** 393215 points

Hi,

Please post which Linux version you use. Make sure that the pinmux settings are not overwritten elsewhere in the device tree.

0 yimin bai34 over 7 years ago in reply to Biser Gatchev-XID

Genius 4755 points

Hi Sir

we used latest SDK for development

0 Bin Liu over 7 years ago in reply to yimin bai34

TI__Guru**** 174761 points

Hi,

Your DTS setting above seems to be correct, so please ensure those two pins are indeed used on your board for UART4 and the pinmux setting is not overwritten elsewhere.

0 Dwarakesh Radhakrishnan over 7 years ago in reply to Bin Liu

Guru 13660 points

Hi,

As suggested by Bin and Biser, you can check if the UART4 pinmux has been overwritten, using devmem2 tool once linux boots
# devmem2 0x44E10968
# devmem2 0x44E1096c

0 yimin bai34 over 7 years ago in reply to Dwarakesh Radhakrishnan

Genius 4755 points

Hi Sir

the result is as below

# devmem2 0x44E10968 ->0x31
# devmem2 0x44E1096c ->0x01

It seems UART2 pinmux has not been overwritten. And the uart4 has no message output

BR
Yimin

0 Dwarakesh Radhakrishnan over 7 years ago in reply to yimin bai34

Guru 13660 points

Hi,

As Bin Liu suggested, can you check if the pins probed for UART4 txd and UART4 rxd are F18(E17 for ZCZ package) and F19(E18 for ZCZ package) respectively ?

Please find other pins that can be configured for UART4. Confirm if they are the right pins, otherwise, you need to set pinmuxing in different set of registers. Also how do you access the UART4, can you share the piece of code being used ?

0 Bin Liu over 7 years ago in reply to yimin bai34

TI__Guru**** 174761 points

Hi, I haven’t heard back from you, I’m assuming you were able to resolve your issue. If not, just post a reply below (or create a new thread if the thread has locked due to time-out). thanks.

Processors

Processors forum

Linux/AM3352: About UART4 Issue