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authorAndreas Fritiofson <andreas.fritiofson@gmail.com>2017-01-03 00:18:34 +0100
committerPaul Fertser <fercerpav@gmail.com>2017-01-15 10:38:51 +0000
commit52a396656aee2227fad8c9b54576ffec571e7e3e (patch)
tree603ac1d8130848c127e96766ec4d662066ca98ba
parent7436f7c2c0318fabce777d8886b302e3ca128606 (diff)
doc: Improve ftdi driver section
Fix typo and a sentence that sounds strange since the ft2232 driver was removed. Add documentation for the SWD signal usage. Remove the text mentioning a default VID:PID which doesn't exist. Change-Id: I27eba571f2f7c46bdb6ae623ab285595018e99d9 Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com> Reviewed-on: http://openocd.zylin.com/3935 Tested-by: jenkins Reviewed-by: Paul Fertser <fercerpav@gmail.com>
-rw-r--r--doc/openocd.texi18
1 files changed, 11 insertions, 7 deletions
diff --git a/doc/openocd.texi b/doc/openocd.texi
index 8c10a269..5977c409 100644
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -2408,11 +2408,10 @@ This driver is for adapters using the MPSSE (Multi-Protocol Synchronous Serial
Engine) mode built into many FTDI chips, such as the FT2232, FT4232 and FT232H.
The driver is using libusb-1.0 in asynchronous mode to talk to the FTDI device,
-bypassing intermediate libraries like libftdi of D2XX.
+bypassing intermediate libraries like libftdi or D2XX.
-A major improvement of this driver is that support for new FTDI based adapters
-can be added competely through configuration files, without the need to patch
-and rebuild OpenOCD.
+Support for new FTDI based adapters can be added competely through
+configuration files, without the need to patch and rebuild OpenOCD.
The driver uses a signal abstraction to enable Tcl configuration files to
define outputs for one or several FTDI GPIO. These outputs can then be
@@ -2421,6 +2420,12 @@ are reserved for nTRST, nSRST and LED (for blink) so that they, if defined,
will be used for their customary purpose. Inputs can be read using the
@command{ftdi_get_signal} command.
+To support SWD, a signal named SWD_EN must be defined. It is set to 1 when the
+SWD protocol is selected. When set, the adapter should route the SWDIO pin to
+the data input. An SWDIO_OE signal, if defined, will be set to 1 or 0 as
+required by the protocol, to tell the adapter to drive the data output onto
+the SWDIO pin or keep the SWDIO pin Hi-Z, respectively.
+
Depending on the type of buffer attached to the FTDI GPIO, the outputs have to
be controlled differently. In order to support tristateable signals such as
nSRST, both a data GPIO and an output-enable GPIO can be specified for each
@@ -2439,9 +2444,8 @@ These interfaces have several commands, used to configure the driver
before initializing the JTAG scan chain:
@deffn {Config Command} {ftdi_vid_pid} [vid pid]+
-The vendor ID and product ID of the adapter. If not specified, the FTDI
-default values are used.
-Currently, up to eight [@var{vid}, @var{pid}] pairs may be given, e.g.
+The vendor ID and product ID of the adapter. Up to eight
+[@var{vid}, @var{pid}] pairs may be given, e.g.
@example
ftdi_vid_pid 0x0403 0xcff8 0x15ba 0x0003
@end example