Using UART2 of our custom am3352 board

Thilo Cestonaro

Other Parts Discussed in Thread: AM3352

Hey!

I want to use the UART2 of our custom am3352 board. Uart2 rx and tx are connected to mii1_tx_clk and mii1_rx_clk.

I did the muxing of 0x12c to be an INPUT and 0x130 to be an OUTPUT:

static struct module_pin_mux uart2_pin_mux[] = {
	{OFFSET(mii1_txclk), (MODE(1) | PULLDOWN_EN | RXACTIVE)}, /* UART2_RXD */
	{OFFSET(mii1_rxclk), (MODE(1) | PULLUP_EN)},		  /* UART2_TXD */
	{-1},
};

With this muxing and the following cmper module enabling the uart2 should be working in my understanding:

enable_clock_module(&cmper->l4lsclkctrl,  MODULE_CLKCTRL_MODULEMODE_SW_EXPLICIT_EN, 1);
enable_clock_module(&cmper->uart2clkctrl, MODULE_CLKCTRL_MODULEMODE_SW_EXPLICIT_EN, 1);

But the only working direction is the rx. So I can receive data send to UART2 but when I want to loopback this data, there is nothing happening. Any hints what can be wrong here? Regards Thilo

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

First thing to check is whether the pinmux for the TX pin does not get overwritten. You can dump the pinmux register contents with devmem2 and check this.

0 Thilo Cestonaro over 9 years ago in reply to Biser Gatchev-XID

Prodigy 100 points

Thanks for your quick reply. I double checked this already, even created a uboot command which does the redirect directly in uboot.

Nevertheless, the pinmux is not overwritten by the kernel.

I get 0x21 for the RX Pin and 0x11 for the TX which is exactly Input Pulldown and Output Pullup.

U-Boot# md 0x44e1092c 2
44e1092c: 00000021 00000011                      !.......

root@ct-d335x:~# memutil 0x44E1092c w 2
44E1092C | 00000021 00000011

Ok, I didn't use devmem2 but the memutil does the same thing. :)

Further Ideas?

0 Biser Gatchev-XID over 9 years ago in reply to Thilo Cestonaro

TI__Guru**** 393215 points

I have asked the software team to help on this. Please post which Linux version you use.

0 Thilo Cestonaro over 9 years ago in reply to Biser Gatchev-XID

Prodigy 100 points

We use a selfbuild linux derived from openembedded core and yocto, build via bitbake.
The Kernel is a 3.14.10 with the beaglebone black patches and some changes of us.
The Uboot is derived from 2014.07.

0 Kemal R. Shakir over 9 years ago in reply to Thilo Cestonaro

TI__Guru 55345 points

Hello Thilo,

Have you noticed the rgmii1_pin_mux and mii1_pin_mux structures they also contains these two pin-outs muxed. You may check the kernel's device tree too, since the cpsw will reinitialize them.

Best regards,
Kemal

0 Thilo Cestonaro over 9 years ago in reply to Kemal R. Shakir

Prodigy 100 points

Thanks a lot for your hint. Theses pins are already removed in our dts cpsw pinmux and I double checked, that they are not muxed in any includes.

So sadly not fixed yet :(

Regards
Thilo

0 Kemal R. Shakir over 9 years ago in reply to Thilo Cestonaro

TI__Guru 55345 points

How do you loop these data back? In case of serial communication program, you have disabled the HW flow control right?

0 Thilo Cestonaro over 9 years ago in reply to Kemal R. Shakir

Prodigy 100 points

for Uboot Loopback: 0x4802400C => LCR 0x48024008 => EFR with LCR[7] = 1

U-Boot# md.l 0x4802400C 1
4802400c: 00000000                               ....
U-Boot# mw.l 0x4802400C 0x80
U-Boot# md.l 0x48024008 1
48024008: 00000001                               ....

Then I have a command which does this:

#define SERIAL eserial3_device
extern struct serial_device SERIAL;

SERIAL.start(); // Inits LCR 0x03, MDR1 0x0, MCR 0x03, FCR 0x07, dll 0x1A, dlm 0x0
while(1) {
	msleep(100);
	if(SERIAL.tstc()) {
		char c = SERIAL.getc();
		if(c == 'q')
			break;
		SERIAL.putc(c);
		printf("%c", c);
	}
}

So I guess Hardware Flow is disabled. Right? Or did I miss something?
Regards
Thilo

0 Thilo Cestonaro over 9 years ago in reply to Thilo Cestonaro

Prodigy 100 points

Thanks to all who tried to help! In the end it was a borken cable :( ...

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Using UART2 of our custom am3352 board