This is my third post on the TI FR2xx microcontrollers that feature FRAM memory. The links to the previous posts are at the bottom of this post.
The small breadboard breakout I designed for the FR2000 and FR2011 arrived in the mail today. I was lucky and OshPark put my PCB alongside a rush order and I received it one week from submission - great! I soldered it up and got it to blink without a problem - again, great! In this post I will describe the board, show the schematic and update where I am in my explorations of small microcontrollers with FRAM.
The rows of breakout pins are placed 0.6 inches apart on 0.1 inch pitch so that it fits easily onto a standard breadboard with room to access the pins on the side. Here it is, flashing away and powered by the LaunchPad that was used to upload the firmware:
The schematic is below:
It has the basics needed to program and run the microcontroller from the eZ-FET on a LaunchPad plus provision for a LED on board if desired. The FR2000 and FR2111 are pin compatible so either can be used. All external pins are accessible. I chose not to provide for an external crystal since I don't expect to need it in my project. The microcontroller has a TSSOP form factor and the passives are all 0805 SMD. If anyone is interested I will make the gerbers open on OshPark or send the KiCad files.
A key objective of my project is to store incoming data into FRAM and then have it persist when power is removed. The data will then be retrieved when power is restored by sending it out over serial to a PC or other device. I have FRAM working in persist mode now as described in the last post and also have the ring buffer working from a previous project done on a MSP430F5529 which should port easily since it is just C code. It looks at the moment like everything will fit in the FR2111 which is nice since it is inexpensive and easy to design around. Of course, not everything is going well.
Over the weekend I worked a bit on bog standard serial over the UART and for some reason couldn't get it to work on the FR2433. I didn't expect a problem with serial as I have used it on the F5529 and other MSP430s a fair amount and never had a problem. I still haven't figured out what I am doing wrong after spending considerable time in debug mode on CCS and then hauling out the logic analyzer. I know I am in trouble when the logic analyzer comes out. But something in the back of my mind tells me I have seen the problem before, but I just can't place it. Anyway, now I will change over to the FR2111 and see how I do with that.