Specifications

Panasonic PAN4555 (SNAP Engine Form Factor)
In addition to the existing line of Synapse RF Engines, SNAP 2.2 is also available as a SNAP Engine
based on Panasonic’s PAN4555 module. Like the other SNAP Engines, this PAN4555 board has 24
pins, and supports 19 GPIO. These two types of modules are largely interchangeable. However, there
are a few functional differences to be aware of:
Fewer “Wakeup” Pins
On a Synapse RF100 Engine, GPIO pins GPIO1, GPIO2, and GPIO5 can be used to wake the module
from “sleep mode.” On a Panasonic PAN4555 Wireless Module, GPIO pins 1, 2, and 5 cannot wake
the processor. Note that GPIO pins 1, 2, and 5 can be used as inputs, and they can be monitored. Only
the “wakeup” functionality is missing.
GPIO pins 6, 9, and 10 can be used to wake from sleep mode on both Synapse RFEs and PAN4555
wireless modules.
Fewer ADC Input Pins
On a Synapse RF100 Engine, GPIO pins GPIO11 through GPIO18 can all be used as Analog to
Digital Converter (ADC) inputs. On the PAN4555 Wireless Module, only GPIO 11, 16, 17, and 18
support ADC. This means only ADC channels 0, 1, 2, and 7 provide live readings.
You cannot “cheat” and read/write 8 GPIO with a single poke()
On a Synapse RF100 Engine, GPIO pins GPIO11 through 18 are all mapped to the same I/O register
on the microcontroller. This means these pins can be used to easily implement an 8-bit wide data bus
(see for example script “lcd8bit.py”). On the Panasonic PAN4555, the 4 missing ADC pins
(mentioned above) affect this “data bus” as well. You can still write to the 8-bit wide data register, but
only 4 of the pins controlled by that register are actually brought out to the real world.
Two Additional PWM Output Pins
On a Synapse RF100 Engine, only GPIO 0 can perform Pulse Width Modulation (PWM). On the
PAN4555 Wireless Module, GPIO pins 14 and 15 can also do limited
PWM.
The PWM limitation on these two pins (GPIO 14 and 15) has to do with the frequency of the pulse
that can be modulated. On these two pins, the pulses always occur every 1 millisecond. SNAPpy
scripts can affect the width of the pulses, but not the rate at which they occur.
Refer to example script PAN4555_ledCycling.py for one example of using these additional PWM
pins.
If you need a pulse rate different than 1 per millisecond (for example, you are doing servo motor
control), you will have to use GPIO 0.
Page 132 of 202 SNAP Reference Manual Document Number 600-0007K