As I need more GPIOs to control two LTE modules, can I use the following pins:
MPCIE
How should I configure it in the device tree to use it as GPIOs?
Are there also ADC's present? E.g. to measure/montor voltage levels. Or do you use a I2C/SPI based ADC?
When you take a look at the GPIO Reference Card, you will see that Pins 95 (PERST) and 97 (WAKE) have a GPIO number, which means these pins can in fact be used as GPIOs. And you will see that the other pins have no GPIO number, which means they cannot be used as GPIOs. This is generally true for all differential signals, they are typically dedicated.
The PicoCore family has not defined any ADC pins. I would recommend using an I2C chip or, if speed is an issue, an SPI based ADC.
Your F&S Support Team
Thanks!
can do you advice a supported I2C I/O Expander in order to add more GPIOs?
There is a whole set of devices available with the PCA953x driver in Linux. If you look at drivers/gpio/gpio-pca953x.c, you'll find a whole list of devices that are supported by this driver, from additional 4 GPIOs to 40 GPIOs.
Your F&S Support Team
Many thanks, that helps. A final question. I used the GPIO Reference Card, could you just fly over and say if this GPIOs are ok with the MP and MM?
No LVDS needed, no MPCIe needed:
GPIO
GPIO
J1_46/52/54 on MM:
It is not important if you don't need LVDS, it is important if the board is built for LVDS. On MM, we are rather short on GPIOs. Some GPIOs are needed to support internal chips, for example the MIPI to LVDS converter for LVDS output. In this case, these GPIOs are not available on the B2B connector at all. Only on those board variants without LVDS converter, these GPIOs are routed to the B2B connector instead. This means this is a hardware option and depends on the board variant that you order.
J1_63
I believe this should be J2_63 because on J1_63 there is GND.
J2_65/67/69/73/75/77/79
Please note the different voltages on MM (3.3V) and MP (1.8V). You may need to add a level shifter to be prepared for both variants. Again on MM, these pins are only available on those board variants where no Security Chip and no CAN is equipped.
I'm not sure if you are aware of this, but you can also use most of the dedicated pins as GPIOs if you do not need that dedicated function. For example if you do not need two SPI ports or even none at all, then you can use the free SPI pins as GPIOs, too. The same for I2C, UART and SD. In fact this may even be more compatible between boards. Because when we design a new PicoCore variant, we try to fill the dedicated functions first and all remaining GPIO pins on the connector are filled with all the remaining GPIOs. Which means there are the most variations from board to board, depending on "what is left over" in each case.
Your F&S Support Team
Ok, understood and make sense. What about
Can this be used on both MM and MP?
We decided to go for the Plus model only. So are this GPIOs valid for all Plus variants or at least for variants V3I-LIN and V3XI-LIN?
GPIO
Looks good to me.
Your F&s Support Team
