User manual

Code Mercenaries
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10. ESD Considerations
JoyWarrior has an internal ESD protection to
withstand discharges of more than 2000V without
permanent damage. However ESD may disrupt
normal operation of the chip and cause it to exhibit
erratic behaviour.
For the typical office environment the 2000V
protection is normally sufficient. Though for
industrial use additional measures may be
necessary.
When adding ESD protection to the signals special
care must be taken on the USB signal lines. The
USB has very low tolerance for additional
resistance or capacitance introduced on the USB
differential signals.
Series resistors of 27Ω may be used alone or in
addition to some kind of suppressor device. In any
case the USB 2.0 specification chapter 6 and 7
should be read for detailed specification of the
electrical properties.
10.1 EMC Considerations
JoyWarrior uses relatively low power levels and so
it causes few EMC problems.
To avoid any EMC problems the following rules
should followed:
• Put the 100nF ceramic capacitor right next to
the power supply pins of the chip and make sure
the PCB traces between the chips power pins
and the capacitor are as short as possible.
• Run the power supply lines first to the capacitor,
then to the chip.
• Make the matrix lines only as long as absolutely
necessary.
• Keep the two USB signal lines close to each
other, route no other signal between them. USB
uses differential signalling so the best signal
quality with lowest RF emission is achieved by
putting these lines very close to each other.
• Adding a ferrite bead to the +5V power supply
line is advisable.
11. Revision History
The initial release version of JoyWarrior is
V1.0.2.0, earlier versions were custom designs not
available for general use.
V1.0.4.1
- First shipping version of JW24A8L and
JW24A10L
V1.0.4.0
- Discontinued JW20 branch of chips.
- Added JW24A8L and JW24A10L
- Added JW24F14 (aka Tomcat) acceleration
sensor.
V1.0.3.B
- Fixed a spurious enumeration problem with
JW20 variants on Linux. JW24 chips are not
affected. On UHCI hosts it was possible that
reading the device descriptors could fail.
Windows and MacOS were not affected due to a
different error recovery method of their system
drivers.
V1.0.3.A
- Customer specific chips, no general release
V1.0.3.9
- Customer specific chips, no general release
V1.0.3.8
- Added MW24F8 variant
- Fixed a race condition in JW24F8 that could
lead to wrong data when values were jittering
around a 256 boundary.
V1.0.3.7
- Added MW24H8 variant
V1.0.3.6
- Added JW24F8 variant
V1.0.3.5
- Added Zhen Hua protocol to JW24RC
V1.0.3.4
- Added customer specific chips
- Changed reset timing for JW20 variants.
- Not a general release!
V1.0.3.3
- Added MouseWarrior24J8.
- Removed jitter filter on JW20A8 and
JW20A10.
- Relaxed timing of matrix scan function of
JW20A8-16 and JW20A10-16.
- Added direct connected button mode on
JW24GP32 allowing 12 buttons connected
pulling to ground instead of using a matrix.
V1.0.3.2
- Release for customer specific chips, not
generally available.
V1.0.3.1
- Fixed a problem in JW24RC that could cause it
not to detect the correct signal polarity of the
PPM signal.
V 1.1.0, July 1st 2010 for Chip Revision V1.0.4.0 and up