Hi Jacob,

1/ Test is an unused feature at present, you can treat it like a GPIO

2/ We use an opto-isolator so we don't have to provide a switch to the external radios PTT circuit. An electro-mechanical relay would have been an alternative. It's usually a mechanical switch on your PTT mic.
- David

On 08/03/18 00:22, Jacob Falzon wrote:
Hello again,

there are another two pins for the SM1000 that I wanted to know more about.

The Test pin connects to a Self-Test circuit. What exactly is this used to test for please? Also there is another pin named CPPT that connects to an optoisolator. I understand that the CPPT signal is used to trigger the PTT for the radio but why is the opto-isolator implemented please?

Thank you very much for your attention.

Kindest regards,



On Sat, Feb 24, 2018 at 9:01 PM, Jacob Falzon <jacobfalzon2...@gmail.com <mailto:jacobfalzon2...@gmail.com>> wrote:

    Thank you very much for your attention.

    Have a good night!

    On 24 Feb 2018 8:26 PM, "David Rowe" <da...@rowetel.com
    <mailto:da...@rowetel.com>> wrote:

        Hi Jacob,

        These pins are just broken out as GPIOs or for future expansion.

        - David

        On 25/02/18 00:54, Jacob Falzon wrote:

            Hi there,

            i was looking at the schematic and I came upon the SPI pins
            and the UART pins in the schematic.

            The SPI pins ( SCK, MOSI, MISO, NSS) do not seem to be
            connected with an external component. What is their purpose?

            Also the UART pins whilst available are they currently
            utilised for some purpose?

            Many thanks for your kind attention.

            Regards,



            
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