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EHS5: sysstart not sent | Thales IoT Developer Community

July 26, 2016 - 11:59am, 3470 views

Hi everybody,

at the moment I am facing a serious problem concerning EHS5.

Short:

EHS5 does not send sysstart, even though CTS0 (probably*) indicates that ASC0 interface is ready.

Long:

EHS5 shall work as a slave. It is supplied with 3,7V @ 600mA using ~150mA at ***. I tried with 2000mA but it is the same result.

I tried RX and TX lines (yes, they are connected correctly, I simulated the uC with an FTDI cable connected the other way round). RX line works correctly from uC to EHS5 (incl. levelshifters), my logic analyzer says I send AT from uC.

Level shifters in TX line are working correctly (I tried this), but EHS5 does not send anything. The rest of startup behavior mentioned in Hardware Interface Description for ASC0 is (probably*) correct.

Probably* means: See the attached picture. Yellow line is the TX and the other is CTS0. The little spike in TX looks like a discharge of a capacitor. So I think the module is turned off and on again, then java crashes and sysstart is never sent. I even waited 3 seconds from CTS0_low for sysstart. I tested two boards and both have the same problem. The polarized cap has 150uF.scope picture

I hope to get some ideas where I could check next.

Thanks a lot and best regards

Hieronymus