[openocd-svn] Main OpenOCD repository branch, master, updated. v0.4.0-121-g3b310db

[David B. <dbr...@us...>]

This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "Main OpenOCD repository".

The branch, master has been updated
       via  3b310dbac5ae1db7fb768aa0789bbe101137c7e1 (commit)
      from  7373d1c342ff0ef5c0663fcee2f688eb5eb4ef65 (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.

- Log -----------------------------------------------------------------
commit 3b310dbac5ae1db7fb768aa0789bbe101137c7e1
Author: David Brownell <dbr...@us...>
Date:   Fri Mar 19 10:31:44 2010 -0700

    FT2232 comment tweaks
    
    Note that the FT4232 chips have four channels not two, and
    Elaborate on uses of the additional channels.
    
    Signed-off-by: David Brownell <dbr...@us...>

diff --git a/src/jtag/drivers/ft2232.c b/src/jtag/drivers/ft2232.c
index b45e8a4..8e835c5 100644
--- a/src/jtag/drivers/ft2232.c
+++ b/src/jtag/drivers/ft2232.c
@@ -32,12 +32,24 @@
  * JTAG adapters based on the FT2232 full and high speed USB parts are
  * popular low cost JTAG debug solutions.  Many FT2232 based JTAG adapters
  * are discrete, but development boards may integrate them as alternatives
- * to more capable (and expensive) third party JTAG pods.  Since JTAG uses
- * only one of the two ports on these devices, on integrated boards the
- * second port often serves as a USB-to-serial adapter for the target's
- * console UART even when the JTAG port is not in use.  (Systems which
- * support ARM's SWD in addition to JTAG, or instead of it, may use that
- * second port for reading SWV trace data.)
+ * to more capable (and expensive) third party JTAG pods.
+ *
+ * JTAG uses only one of the two communications channels ("MPSSE engines")
+ * on these devices.  Adapters based on FT4232 parts have four ports/channels
+ * (A/B/C/D), instead of just two (A/B).
+ *
+ * Especially on development boards integrating one of these chips (as
+ * opposed to discrete pods/dongles), the additional channels can be used
+ * for a variety of purposes, but OpenOCD only uses one channel at a time.
+ *
+ *  - As a USB-to-serial adapter for the target's console UART ...
+ *    which may be able to support ROM boot loaders that load initial
+ *    firmware images to flash (or SRAM).
+ *
+ *  - On systems which support ARM's SWD in addition to JTAG, or instead
+ *    of it, that second port can be used for reading SWV/SWO trace data.
+ *
+ *  - Additional JTAG links, e.g. to a CPLD or * FPGA.
  *
  * FT2232 based JTAG adapters are "dumb" not "smart", because most JTAG
  * request/response interactions involve round trips over the USB link.

-----------------------------------------------------------------------

Summary of changes:
 src/jtag/drivers/ft2232.c |   24 ++++++++++++++++++------
 1 files changed, 18 insertions(+), 6 deletions(-)


hooks/post-receive
-- 
Main OpenOCD repository