From: Steven A. Falco <sfalco@harris.com>
To: u-boot@lists.denx.de
Subject: [U-Boot-Users] Sequoia uart support looks to be misconfigured
Date: Fri, 01 Aug 2008 13:10:23 -0400 [thread overview]
Message-ID: <4893437F.9030802@harris.com> (raw)
I am looking at U-Boot version "DENX-v1.3.3" for the AMCC Sequoia board
(PPC440EPx).
The uart gpio configuration doesn't appear to match the schematics.
sequoia.h has the following GPIO settings:
{GPIO1_BASE, GPIO_OUT, GPIO_ALT3, GPIO_OUT_1}, /* GPIO34 UART0_DCD_N
UART1_DSR_CTS_N UART2_SOUT*/ \
{GPIO1_BASE, GPIO_IN , GPIO_ALT3, GPIO_OUT_0}, /* GPIO35
UART0_8PIN_DSR_N UART1_RTS_DTR_N UART2_SIN*/ \
{GPIO1_BASE, GPIO_IN , GPIO_ALT3, GPIO_OUT_0}, /* GPIO36
UART0_8PIN_CTS_N EBC_DATA(0) UART3_SIN*/ \
{GPIO1_BASE, GPIO_BI , GPIO_ALT2, GPIO_OUT_0}, /* GPIO37 UART0_RTS_N
EBC_DATA(1) UART3_SOUT*/ \
These look wrong. For example, GPIO34 (ball C28) is wired as CTS
according to the Sequoia schematic. So, shouldn't it be GPIO_ALT2
rather than GPIO_ALT3? Similarly, GPIO35 (ball C29) should be RTS,
which is also GPIO_ALT2 rather than GPIO_ALT3.
GPIO36 (ball A29) is also a CTS signal, so I think this should be
GPIO_ALT1, not GPIO_ALT3. Finally, GPIO37 (ball B29) is another RTS
signal, so it should be GPIO_ALT1, not GPIO_ALT2.
One final comment. In order to use two uarts, SDR0_PFC1[U0IM] must be
set to 1. To select the RTS/CTS function for the first uart,
SDR0_PFC1[U0ME] must be set to 1. Yet, I have not found any place in
the sequoia initialization code where these bits are set. So, I think
the board is actually running with one uart in 8-pin mode rather than
two uarts each in 4-pin mode.
I'd appreciate it if someone else could take a look at this, and comment
on my concerns.
Steve
reply other threads:[~2008-08-01 17:10 UTC|newest]
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