RESET_IN_N doesn't work for HL8518

IoT Modules Legacy HL Series
1

Hello,
I am using RESET_IN_N low for 20ms to reset my HiloNCV2, HL6528RD and HL8518 when I get no answer from AT commands.
This works perfectly on HiloNCV2 and HL6528RD but not on HL8518.
With HL8518, after a RESET_IN_N low for 20ms, I get no more responses. I have to do a start up sequence in order to make it work again.
Any idea why it behaves so?
Best regards,
Thomas

2

Hi hestia,

Please refer to the HL8518 PTS V9.0:
https://source.sierrawireless.com/resources/airprime/hardware_specs_user_guides/airprime_hl8518_hl8528_and_hl8529_product_technical_specification/

As RESET_IN_N is internally pulled up, a simple open collector or open drain transistor can be used to control it.

To reset the module, a low pulse must be sent on RESET pin during 10ms. In the meanwhile, PWR_ON signal must be in logic low.

Please do not link Reset signal pin to a level shifter which voltage level was provided by VGPIO.

when resetting the module, VGPIO collapses and reset gets a "strange" behavior which is not supported by the module.