User manual

Code Mercenaries
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10. ESD Considerations
IO-Warrior56 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.
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
IO-Warrior uses relatively low power levels and so
it causes few EMC problems. The most important
issue is to provide a very clean layout for the
power supply. IO-Warrior56 runs at 24MHz
internal clock rate, this can cause current spikes if
the supply lines are not carefully layed out.
To avoid any EMC problems the following rules
should be followed:
• Keep the PCB traces from the resonator to the
chip pins as short as possible.
• Put the 100nF ceramic capacitors 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.
• Connect the second ground and supply pin in
the shortest possible way to the first ground and
supply pin. No other things may have
precedence over this.
• 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.
11. Revision History
IO-Warrior56 does not use the same code base as
IO-Warrior24 and IO-Warrior40, so the version
numbers are not identical.
1.1.0.1
Feature release.
IIC multi master capability added.
Some invalid combinations on IIC now generate
errors, older versions could hang the IIC function
on violations of start/stop sequences.
Disabling pull-up resistors for low voltage
compatibility added to IIC, SPI, and LCD
functions.
1.1.0.0
Not released due to a bug.
1.0.0.2
Bugfix release. A problem in the USB stack was
fixed that had resulted in malfunctioning chips.
This was a production issue.
1.0.0.1
Initial release
1.0.0.0
Not released due to a bug.
V 1.0.3, November 6nd 2012 for chip version V1.1.0.1