Caveats, Versions, E. serial-to-i²c app – Pololu Wixel User Manual
Page 40: Overview, Installation instructions, Default pinout
Caveats
• If data is received on the ASCII_RX or BINARY_RX pins too quickly, it could result in the internal buffers
filling up and data loss. This app has 512 bytes of buffer space for the ASCII-to-binary conversion and 512 bytes
of buffer space for the binary-to-ASCII conversion.
Caution:
The Wixel’s I/O lines are not 5V tolerant. You must use level-shifters, diodes, or voltage dividers
to connect the Wixel to outputs from 5V systems. Also, avoid drawing more current from an I/O line than
it can provide (see the discussion of maximum pin current in
). Avoid connecting multiple
output pins together.
The Wixel does not support the RS-232 voltage levels typically used by DB9 serial ports. The Wixel’s I/O
lines, including the RX and TX lines, operate on voltages between 0 and 3.3 V. To connect the Wixel to an
RS-232 serial signal, you will need additional level-shifting and inverting hardware like the
(RS-232 serial is inverted; the Wixel’s serial interface
expects non-inverted serial).
Versions
•
(17k wxl), released 2013-06-06: Initial release.
9.e. Serial-to-I²C App
Overview
This app turns a Wixel into a serial-to-I²C bridge, acting as a master controller on a single-master I²C bus. To perform
I²C operations, another device can issue serial ASCII commands to the Wixel on its radio, UART, or USB interface.
is a two-wire interface that is commonly used for communications on peripherals
like the
and the
The
(371k pdf) for the I²C bus is published by NXP.
Installation Instructions
Download the
(26k wxl).
Open it with the Wixel Configuration Utility, choose your parameters, and then write it to a Wixel. See
for
more information on how this is done.
Default Pinout
Pin
Function
P1_0 SCL I²C clock (0–3.3 V)
P1_1 SDA I²C data (0–3.3 V)
P1_6 TX
transmits serial data (0–3.3 V)
P1_7 RX
receives serial data (0–3.3 V)
Pololu Wixel User's Guide
© 2001–2014 Pololu Corporation
9. Wixel Apps
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