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From: Jon Hunter <jon-hunter@ti.com>
To: Sourav <sourav.poddar@ti.com>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
	Kevin Hilman <khilman@deeprootsystems.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tony Lindgren <tony@atomide.com>,
	linux-serial@vger.kernel.org, linux-omap@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Alan Cox <alan@linux.intel.com>
Subject: Re: [RFC 00/24] OMAP serial driver flow control fixes, and preparation for DMA engine conversion
Date: Thu, 11 Oct 2012 09:05:22 -0500	[thread overview]
Message-ID: <5076D222.5080600@ti.com> (raw)
In-Reply-To: <50769D8C.8030401@ti.com>

Hi Sourav,

On 10/11/2012 05:21 AM, Sourav wrote:

[snip]

> I already enable software flow control and did the testing on beagle,
> where things are working fine
> after off mode.
> But if I enable hardware flow control, the teraterm does not allow me to
> load my fs and uImage from mmc.
> If you have any pointers on how to test hardware flow control, I will
> like to do that on my beagle board.

For h/w flow control, you need to check if the CTS and RTS signals are
being brought out to the serial header on the beagle-board. Looking at
the schematics for the 3430 beagle board, it appears that only the UART
RX and TX signals are available on the serial header. Therefore, I don't
believe you can test h/w flow control using the console with that board.

I do see that you can access all the UART2 signals (RX/TX/CTS/RTS) via
the expansion connector on the beagle. However, to connect to a serial
port on a PC you need to have a voltage level-shifter in-between. There
are some companies out there that make them [1], but you need to make
sure you have one that can support a 1.8V input.

Cheers
Jon

[1] http://elinux.org/RS232_Level_Shifter

WARNING: multiple messages have this Message-ID (diff)
From: jon-hunter@ti.com (Jon Hunter)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC 00/24] OMAP serial driver flow control fixes, and preparation for DMA engine conversion
Date: Thu, 11 Oct 2012 09:05:22 -0500	[thread overview]
Message-ID: <5076D222.5080600@ti.com> (raw)
In-Reply-To: <50769D8C.8030401@ti.com>

Hi Sourav,

On 10/11/2012 05:21 AM, Sourav wrote:

[snip]

> I already enable software flow control and did the testing on beagle,
> where things are working fine
> after off mode.
> But if I enable hardware flow control, the teraterm does not allow me to
> load my fs and uImage from mmc.
> If you have any pointers on how to test hardware flow control, I will
> like to do that on my beagle board.

For h/w flow control, you need to check if the CTS and RTS signals are
being brought out to the serial header on the beagle-board. Looking at
the schematics for the 3430 beagle board, it appears that only the UART
RX and TX signals are available on the serial header. Therefore, I don't
believe you can test h/w flow control using the console with that board.

I do see that you can access all the UART2 signals (RX/TX/CTS/RTS) via
the expansion connector on the beagle. However, to connect to a serial
port on a PC you need to have a voltage level-shifter in-between. There
are some companies out there that make them [1], but you need to make
sure you have one that can support a 1.8V input.

Cheers
Jon

[1] http://elinux.org/RS232_Level_Shifter

  parent reply	other threads:[~2012-10-11 14:05 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-06 12:38 [RFC 00/24] OMAP serial driver flow control fixes, and preparation for DMA engine conversion Russell King - ARM Linux
2012-10-06 12:38 ` Russell King - ARM Linux
2012-10-06 12:39 ` [RFC 01/24] SERIAL: omap: fix set_mctrl() breakage Russell King
2012-10-06 12:39   ` Russell King
2012-10-06 12:39 ` [RFC 02/24] SERIAL: omap: fix bit masks for software flow control Russell King
2012-10-06 12:39   ` Russell King
2012-10-06 12:40 ` [RFC 03/24] SERIAL: omap: remove setting of EFR SCD bit Russell King
2012-10-06 12:40   ` Russell King
2012-10-06 12:40 ` [RFC 04/24] SERIAL: omap: fix MCR TCRTLR bit handling Russell King
2012-10-06 12:40   ` Russell King
2012-10-06 12:40 ` [RFC 05/24] SERIAL: omap: no need to re-read EFR Russell King
2012-10-06 12:40   ` Russell King
2012-10-06 12:41 ` [RFC 06/24] SERIAL: omap: allow hardware assisted rts/cts modes to be disabled Russell King
2012-10-06 12:41   ` Russell King
2012-10-06 12:41 ` [RFC 07/24] SERIAL: omap: allow hardware assisted IXANY mode " Russell King
2012-10-06 12:41   ` Russell King
2012-10-06 12:41 ` [RFC 08/24] SERIAL: core: use local variable uport in uart_set_termios() Russell King
2012-10-06 12:41   ` Russell King
2012-10-06 12:42 ` [RFC 09/24] SERIAL: core: add hardware assisted s/w flow control support Russell King
2012-10-06 12:42   ` Russell King
2012-10-06 12:42 ` [RFC 10/24] SERIAL: core: add hardware assisted h/w " Russell King
2012-10-06 12:42   ` Russell King
2012-10-06 12:42 ` [RFC 11/24] SERIAL: core: add throttle/unthrottle callbacks for hardware assisted flow control Russell King
2012-10-06 12:42   ` Russell King
2012-10-06 12:43 ` [RFC 12/24] SERIAL: omap: fix " Russell King
2012-10-06 12:43   ` Russell King
2012-10-06 12:43 ` [RFC 13/24] SERIAL: omap: configure xon/xoff before setting modem control lines Russell King
2012-10-06 12:43   ` Russell King
2012-10-06 12:43 ` [RFC 14/24] SERIAL: omap: serial_omap_configure_xonxoff() contents into set_termios Russell King
2012-10-06 12:43   ` Russell King
2012-10-06 12:44 ` [RFC 15/24] SERIAL: omap: don't read back LCR/MCR/EFR Russell King
2012-10-06 12:44   ` Russell King
2012-10-06 12:44 ` [RFC 16/24] SERIAL: omap: simplify Russell King
2012-10-06 12:44   ` Russell King
2012-10-06 12:44 ` [RFC 17/24] SERIAL: omap: always set TCR Russell King
2012-10-06 12:44   ` Russell King
2012-10-06 12:45 ` [RFC 18/24] SERIAL: omap: move xon/xoff setting earlier Russell King
2012-10-06 12:45   ` Russell King
2012-10-06 12:45 ` [RFC 19/24] SERIAL: omap: simplify (2) Russell King
2012-10-06 12:45   ` Russell King
2012-10-06 12:45 ` [RFC 20/24] SERIAL: core: add xmit buffer allocation callbacks Russell King
2012-10-06 12:45   ` Russell King
2012-10-06 15:49   ` Alan Cox
2012-10-06 15:49     ` Alan Cox
2012-10-06 16:51     ` Russell King - ARM Linux
2012-10-06 16:51       ` Russell King - ARM Linux
2012-10-06 12:46 ` [RFC 21/24] SERIAL: omap: use tx buffer allocation API Russell King
2012-10-06 12:46   ` Russell King
2012-10-06 12:46 ` [RFC 22/24] SERIAL: omap: typesafe conversion from uart_port to uart_omap_port Russell King
2012-10-06 12:46   ` Russell King
2012-10-06 12:46 ` [RFC 23/24] SERIAL: omap: move driver private definitions and structures to driver Russell King
2012-10-06 12:46   ` Russell King
2012-10-06 12:47 ` [RFC 24/24] SERIAL: omap: remove OMAP_UART_SYSC_RESET and OMAP_UART_FIFO_CLR Russell King
2012-10-06 12:47   ` Russell King
2012-10-06 14:23 ` [RFC 00/24] OMAP serial driver flow control fixes, and preparation for DMA engine conversion Russell King - ARM Linux
2012-10-06 14:23   ` Russell King - ARM Linux
2012-10-06 14:39 ` Russell King - ARM Linux
2012-10-06 14:39   ` Russell King - ARM Linux
2012-10-06 15:35 ` Russell King - ARM Linux
2012-10-06 15:35   ` Russell King - ARM Linux
2012-10-06 15:50 ` Alan Cox
2012-10-06 15:50   ` Alan Cox
2012-10-09 13:34 ` Sourav
2012-10-09 13:34   ` Sourav
2012-10-10 18:29   ` Kevin Hilman
2012-10-10 18:29     ` Kevin Hilman
2012-10-11  9:43     ` Sourav
2012-10-11  9:43       ` Sourav
2012-10-11  9:54       ` Russell King - ARM Linux
2012-10-11  9:54         ` Russell King - ARM Linux
2012-10-11 10:21         ` Sourav
2012-10-11 10:21           ` Sourav
2012-10-11 11:08           ` Russell King - ARM Linux
2012-10-11 11:08             ` Russell King - ARM Linux
2012-10-11 14:05           ` Jon Hunter [this message]
2012-10-11 14:05             ` Jon Hunter
2012-10-12 14:51           ` Grazvydas Ignotas
2012-10-12 14:51             ` Grazvydas Ignotas

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