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authorSimon Glass <sjg@chromium.org>2021-07-24 09:03:37 -0600
committerTom Rini <trini@konsulko.com>2021-08-02 13:32:14 -0400
commit5f4b356121fdb520e4c9bb4fe3483c1a5f93439c (patch)
tree24f72a6bf24307ee96ecdc6ef0d5e6e3eb93ade5 /doc
parent7a4ff7c41bab8b43767eacc0b30ca1573ab6acb1 (diff)
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doc: Add a note about number representation
Mention the default base of U-Boot in the command-line section. Add examples for decimal and octal. Signed-off-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'doc')
-rw-r--r--doc/usage/cmdline.rst31
1 files changed, 31 insertions, 0 deletions
diff --git a/doc/usage/cmdline.rst b/doc/usage/cmdline.rst
index b3dbdb8..2d5127c 100644
--- a/doc/usage/cmdline.rst
+++ b/doc/usage/cmdline.rst
@@ -54,3 +54,34 @@ General rules
calling run with a list of variables as arguments), any failing
command will cause "run" to terminate, i. e. the remaining
variables are not executed.
+
+Representing numbers
+--------------------
+
+Most U-Boot commands use hexadecimal (hex) as the default base, for convenient
+use of addresses, for example::
+
+ => md 1000 6
+ 00001000: 2c786f62 00697073 03000000 0c000000 box,spi.........
+ 00001010: 67020000 00000000 ...g....
+
+There is no need to add a `0x` prefix to the arguments and the output is shown
+in hex also, without any prefixes. This helps to avoid clutter.
+
+Some commands use decimal where it is more natural::
+
+ => i2c dev 0
+ Setting bus to 0
+ => i2c speed
+ Current bus speed=400000
+ => i2c speed 100000
+ Setting bus speed to 100000 Hz
+
+In some cases the default is decimal but it is possible to use octal if that is
+useful::
+
+ pmic dev pmic@41
+ dev: 1 @ pmic@41
+ => pmic write 2 0177
+ => pmic read 2
+ 0x02: 0x00007f