Detailing Pin Multiplexing?

[Siddharth]

Hi Team,

I was following the OSD335x Reference Design Tutorial and I wanted to know more about pin-multiplexing. Can you let me know any resources which can help me understand pin multiplexing better? I am just starting in Linux embedded and it is way more different than the bare metal.

Any help will be appreciated.

Best

Siddharth.

[Neeraj Dantu]

Sid,

Regardless of what yo have already read through, here are some of the things we recommend:

1. Table 4.2 (Pin Attributes) from AM335x Datasheet (http://www.ti.com/lit/ds/symlink/am3358.pdf): This table gives you all the modes of each pin along with IO, reset state, power domain and pull-up/pull-down information you need. Make sure to refer to the ZCZ package ball numbers for OSD335x devices.

2. Table 9.3.1(CONTROL_MODULE Registers) from AM335x Technical Reference Manual (https://www.ti.com/lit/ug/spruh73p/spruh73p.pdf): This table provides information of the registers that can be used to set the pinmuxing.

3. OSD335x design tutorial: Device Tree (https://octavosystems.com/app_notes/osd335x-design-tutorial/osd335x-lesson-2-minimal-linux-boot/linux-device-tree/): Section 1.4 Pin Multiplexing provides an example of multiplexing by setting the pin control registers described above.

4. TI pinmux tool (https://dev.ti.com/pinmux/): This tool will help you organize your pinmuxing based on your system needs. It allows you to look at all the peripherals on the AM335x device. The IO sets for each of the peripherals will provide all the valid combination of pins that can be used for the peripheral. Since the pin numbers of the AM335x device and OSD335x are different, take a look at this pin mapping table: https://octavosystems.com/app_notes/osd335x-family-pin-assignments/ for your hardware design.

5.  Other useful links:

– http://www.righto.com/2017/12/hands-on-with-pocketbeagle-tiny-25.html

– https://cm.e-ale.org/2018/pocketbeagle/pocketbeagle.pdf  Video tutorial: https://www.youtube.com/watch?v=jvgDwkkKtBA

Hope that helps,

Please let us know if you have any questions in particular.

Neeraj

[Peter_John]

Hi…I am using MSP430F5501 controller for low power application in this we are using two GPIO pins 1&2 which are also multiplexed with coparator B.Comparator B have four channels in which two channels are connected to these GPIO pins 1 and 2 and others are connected to another two I/O pins 3 and 4.We are using comparator for these 3&4 pins but we are not using 1&2 pins for comparator even though comparator is turning ON automatically for these 1&2 pins and consuming energy and affecting these GPIO pins as well.So can anybody tell me why this is happening without using those pins for comparator?

[Eshtaartha Basu]

Hello Peter_John,

Are you using any of our OSD335x devices along with MSP430F5501? If yes, can you please provide more information about how they are interfaced?

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