Over a week ago I’ve got a notice that Texas Instruments (TI) is giving away a 50% coupon for MSP430_FRAM related devices. Without hesitation ordered their MSP-EXP430FR5739 TI experimenters board that price went down to $14.50 including free shipping.
With all functionality and on board peripherals included – its a give away. Experimenters board came in nice hard paper package that feels really solid and professional in hands.
Surprisingly (or not) TI didn’t limit inside contents with only development board. It also contained small flayer with fast start note, Mini USB-B cable, couple of 10 pin female headers, small bended 6 pin male header and 32.768kHz SMT micro crystal.
About this 6 pin connector – it seems that TI guys made a mistake when packing contents. This isn’t mentioned in description but thanks anyway – will find where to use it.
MSP-EXP430FR5739 board layout
As development board for such price MSP-EXP430FR5739 board has some valuable stuff on it. It is split in to three regions where first is dedicated to debugging and programming. There is a dedicated MSP430F1612 microcontroller used for this. It communicates to PC via USB. IT uses a dedicated serial to USB converter chip (TUSB3410). With proper Jumpers It also can be used for application USART communications. Probably the most interesting area is a development with many features. The center of this is MSP430FR5739 16-bit microcontroller with 16KB FRAM and 1KB of SRAM. Additionally there are:
- eight LEDs;
- MTC thermistor;
- 3 axis accelerometer;
- footprint for LDR resistor;
- pin connections
- two programmable buttons;
- reset switch.
The third part of board is for connectivity. There are connectors for Wireless daughter cards (Ccxxxx RF) and connection to MSP-EXP430F5438 board which can also be used for prototyping if not used on purpose.
Probably one thing is missing on package – a software CD. I know, everything can be downloaded but this would free for additional downloading of CCS which is quite big for slow internet connections.
Development software and demo code
In order to start using MSP-EXP430FR5739 board you’ll need to download couple packages from TI’s website. First one is a source code package which also contains drivers for serial to USB bridge, GUI for displaying results of demo programs (source code of GUI included).
Here are demo screens for Demo application mode1:
As you can see from tests – FRAM write speed reaches almost 1,8MB/s while Flash write speed is arround to 10kB/s. And endurance of FRAM decreases much slower than Flash.
For developing applications we are going to use Code Composer Studio, which is free for code size limited applications. The limit is set to 16KB which is maximum of out board. Practically no limitations for us this time.
How FRAM works
And in the end of this review lets see at a glance what is a FRAM (FeRAM) memory. It’s so called Ferroelectric Random Access Memory which is nonvolatile. This means it retains its contents even if power is removed. FeRAM storage cell is similar to DRAM where capacitor and access transistor is used. But in FeRAM cell capacitor there is a ferroelectric material refereed referred as PZT (lead zirconate titanate) used.
As electric field is applied across capacitor PZT changes polarity according to electric field position and maintains polarity until it’s changed with new e-field pulse.
FeRAM is a low power nonvolatile memory. Compared to Flash it is over hundred times faster than flash memory and its power consumption is very low comparing to Flash or EEPROM. Additionally its endurance is practically unlimited (rated as 100 Trillion R/W cycles). This makes it ideal for replacing Flash and EEPROM memories.
Sounds really attractive but according to wikipedia there are some technological issues that stops mass transition to FeRAM. Firs of all flash memory density is much higher than FRAM and also it is much cheaper to bake Flash memories as technological process is quite well developed. Ferromagnetic materials used in FRAM have some issues with CMOS compatibility and silicon contamination. Despite these facts we have working examples of MSP430 FRAM microcontrollers. With even more low power they are more attractive for portable and battery operated projects.
Next we will put this baby for some test run. Keep tuned!