I2C RTC on FM430 (PPM A3 (REV D))

[ankushdesai]

We were working on the new Flight Module (Rev D) and we noticed that it has I2C interfaced RTC. Can you provide us with details of the RTC and its interfacing and connection on the FM430 Board. Also I wanted to know the details about the INT pin from RTC to MSP430.

[aek]

Sure.

The RTC chip we use is the STMicro M4181S -- datasheets are available online.
http://www.st.com/stonline/products/literature/ds/10773.pdf

The RTC is a simple, normal I2C RTC, interfaced via the usual SCL_SYS and SDA_SYS lines.

The I2C lines are usually pulled to VCC, but the Rev D architecture permits other options.

Remaining notes can be read directly from the schematics.

------------------

[ankushdesai]

Hey can you please provide me the link for the schematic of the same. we failed to find the schematic on the links provided by you.

quote:

---

Originally posted by aek:
Sure.

The RTC chip we use is the STMicro M4181S -- datasheets are available online.
http://www.st.com/stonline/products/literature/ds/10773.pdf

The RTC is a simple, normal I2C RTC, interfaced via the usual SCL_SYS and SDA_SYS lines.

The I2C lines are usually pulled to VCC, but the Rev D architecture permits other options.

Remaining notes can be read directly from the schematics.

---

[aek]

The RTC is not on the PPM -- it's on the CSK Motherboard / Dev Board -- see their schematics.

------------------

[This message has been edited by aek (edited December 19, 2009).]

[ankushdesai]

It would be great if you could provide us with the name of the "PDF" to look into. for the RTC related schematic.

quote:

---

Originally posted by aek:
The RTC is not on the PPM -- it's on the CSK Motherboard / Dev Board -- see their schematics.

---

[aek]

705-00194d.zip
705-00433d.zip

------------------

[jschooler]

I have been having problems with the Dev board RTC as well. I feel that an on-board clock is such an essential piece of a spacecraft system that it should be easier to interface with the RTC. Would it be too much to request a piece of example C code that has been tested on the Development Board Rev. D with the A3 PPM? I have read every schematic, memo, and data sheet and have wrestled with different initialization and jumper configurations to no avail. It seems like there are many people with this same problem posting on the forums, but no clear answers.

As an aside, I am particularly interested in a set of four jumpers on the intermediary board between the PPM and the Dev Board, labeled I2C Config. Is there no documentation for this board?

Thanks so much! I've been driving myself mad for over a week now trying to communicate with the RTC...

[aek]

Unfortunately there are many issues with TI's MSP430 I2C implementation in the '16x and '26x series ...

1. Do you have an I2C analyzer (e.g. a Beagle)?

2. Do you have I2C working with other peripherals?

In my experience, there is no way you're going to get I2C working without a decent analyzer. We've had no trouble getting e.g. the RTC to talk to a PPM B1 ... but we do not hae release-quality code for the MSP430 and I2C at this time ...

[cscooper]

Aek - can you tell me more about these I2C issues? We are having problems where code that works one day, fails miserably the next, and it's on an MSP430F2618. It would be very helpful for me to learn more about what others are seeing ...

Thanks!
Chris