[FE training-materials-updates] Fix Nunchuk communication mode explanations
Michael Opdenacker
michael.opdenacker at free-electrons.com
Wed Dec 4 15:43:37 CET 2013
Repository : git://git.free-electrons.com/training-materials.git
On branch : master
Link : http://git.free-electrons.com/training-materials/commit/?id=ec016cf8b57259d1dd8a0f1568dc6ce43533dc2d
>---------------------------------------------------------------
commit ec016cf8b57259d1dd8a0f1568dc6ce43533dc2d
Author: Michael Opdenacker <michael.opdenacker at free-electrons.com>
Date: Wed Dec 4 15:37:38 2013 +0100
Fix Nunchuk communication mode explanations
- You don't write a value to a register. You just write bytes
through I2C.
- Apparently, the explanations we had before were for the wiimote,
which has memory-mapped registers.
Signed-off-by: Michael Opdenacker <michael.opdenacker at free-electrons.com>
>---------------------------------------------------------------
ec016cf8b57259d1dd8a0f1568dc6ce43533dc2d
.../kernel-i2c-communication.tex | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/labs/kernel-i2c-communication/kernel-i2c-communication.tex b/labs/kernel-i2c-communication/kernel-i2c-communication.tex
index 5950baf..6fb570a 100644
--- a/labs/kernel-i2c-communication/kernel-i2c-communication.tex
+++ b/labs/kernel-i2c-communication/kernel-i2c-communication.tex
@@ -106,12 +106,12 @@ In the probe routine (run every time a matching device is found):
\item Using the I2C raw API (see the slides), send two bytes to the
device: \code{0xf0} and \code{0x55}
\footnote{There are two ways of communicating with a wiimote extension.
- The first known way was with data encryption by writing the encryption
- byte 0x00 to 0x40. With this way, you have to decrypt each bytes you
+ The first known way was with data encryption by writing two
+ bytes: 0x40 and 0x00. With this way, you have to decrypt each byte you
read from the nunchuk (not so hard but something you have to do).
- Unfortunately, using 0x00 as the encryption byte is not working on third
+ Unfortunately, such encryption doesn't work on third
party nunchuks so you have to set up unencrypted communication by
- writing 0x55 to 0xF0, then writing 0x00 to 0xFB. This is working across
+ writing 0xf0 and 0x55 instead. This works across
all brands of nunchuks (including Nintendo ones).}.
Make sure you check the return value of
the function you're using. This could reveal communication issues.
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