Hackscribble FRAM Hardware
PCB designs for connecting Fujitsu MB85RS Ferroelectric memory (FRAM) to Arduino and LPCXpresso boards.
Created on 20 April 2014 by Ray Benitez
Last modified on 1 December 2014 by Ray Benitez
These hardware designs are licensed by Ray Benitez under the Creative Commons Attribution-Sharealike 4.0 International License.
About the hardware
Level converter circuits
These circuit snippets connect 3.3V MB85RS FRAM chips to 5V Arduino inputs / outputs.
Two design approaches are shown:
Discrete design using BSS108 FETs, following the approach used by the Adafruit level converter.
Integrated design using TXB0104 to reduce PCB space required.
The designs are in Eagle format.
The mini-shield allows up to three 3.3V FRAMS to be connected to an Arduino (or an LPCXPresso board). It uses an extended version of the integrated circuit snippet (above) using a TXB0108. The board has been tested with Arduino Uno and LPCXpresso 11U68 boards.
The design is in KiCad format.
The supply voltage for the Arduino / LPCXpresso side of the level converter is taken from the IOREF output of the Arduino / LPCXpresso. This automatically adjusts for 3.3V or 5V boards.
The REVISION B board also includes test points for monitoring the SPI bus.
1 December 2014
Added mini-shield REVISION C "slim" version.
5 November 2014
Upgraded mini-shield to REVISION B.
1 November 2014
Added mini-shield REVISION A.
20 April 2014
Initial release of level converter circuits REVISION A.