Glo What do the two microcontrollers do?

[SyreKron]

Does anyone know the functions of the two MSP430 micro-controllers on the Glo? One of them (u6) has a watch crystal and I presume that it houses the real time clock and perhaps the power management functions.

The other functions I could imagine being present are battery management and front light control.

As a side note, it does seem to me that the three serial ports on the board are for each of the processors: J5 for U19 (i.mx508), J1 for U6 (MSP430G2333), and and J2 for U38 (MSP430V325?).

I ask because I would like to add some small sensors to (gyro, temperature, etc) to my Kobo and interface them to some of the spare gpio pins on one or both of the micro-controllers.

I know my way around MSP430s and I'd like to have an idea of what I'd have to maintain compatibility with should I decide to replace firmware in one of them.

Thanks!

[hawhill]

Yep, that's basically their functions. The kernel code gives additional hints AFAICS. You probably can't dump their firmware easily, though. I think they were I2C or SPI coupled to the SoC's bus - and probably, plugging onto an existing I2C bus is the easiest way to add your own sensors? It's probably not really worth the hassle to do it indirectly via one of the MSP430s.

[SyreKron]

You're right, the I2C on the i.mx would be the easiest option except that I'd like to have sensors operational while the i.mx is not running. I'd also like to be able to wake the i.mx under certain external conditions.

I also doubt that the MSP430 firmware is readable. I assume that I'd have to figure out its function based on external observation and any available kernel source code.

I was hoping someone else has been down this road and could give me a head start.

[yoq]

I only know about U6:
It does battery-sensing, RTC-functions, (and can reset the device?)
It also generates the PWM for the frontlight: https://www.mobileread.com/forums/att...1&d=1368175933

it gets its commands via i2c from the iMX.
You can look at the interface in the kernel source in : /drivers/mxc/pmic/core/pmic_core_i2c.c
unfortunately i haven't found anything that looks like a firmware update routine

[SyreKron]

I only know about U6

Thank you! That is very helpful information. I think U6 will be my target for additional hardware interfaces since I can get a datasheet for the part (and replacements) and because U6 seems to be powered even when the device is off.

I think my first goal will be to add an accelerometer to the Glo. I could put it on the I2C bus of the SoC itself but I'd like to wake the device via "shake and wake" which requires the powered MCU.

Once (if) I get that working it should be possible to pass the accelerometer data to the Android framework...not that I'm savvy enough to pull that off right now.

I'll order a couple of those MCUs from digikey. Meanwhile it is time to get the oscilloscope and i2c bus analyzer going.

unfortunately i haven't found anything that looks like a firmware update routine

I doubt that there is a firmware update function for U6. If you botched an update to it you could lose control of your power supplies and possibly brick the device.

[RandomInsano]

Bringing this thread back from the dead. I’m presuming the MSP430G2333 handles the Adobe DRM. I have no interest in circumventinging that and the serial headers aren’t especially useful outside of flashing code to it. I confirmed the TX and RX pins go to the SBWTCK and SBWTDIO which again, not really useful.

It’ll be better to piggyback something on that I2C bus.