BC660K-GL Auto-Power-On AND External Watchdog IC (QuecOpen)

IoT Modules LPWA Module
1

Hello,

I am interested to understand if it is possible to configure the BC660K-GL with automatic power on AND an external watchdog IC supervisor such as TPS3823 family of Voltage Monitor With Watchdog Timer.

Planned BC660K-GL Implementation

  • Dedicated DC power Supply (not battery powered), VBAT = 3.3V
  • VDD_SEL mounted with resistor to GND, so that VDD_EXT=VBAT=3.3V
  • QuecOpen (OpenCPU) (when ready on BC660K-GL and I qualify with Quectel Sales)
  • I am speaking with a Quectel sales representative on BC660K-GL and QuecOpen roadmap availability

Questions

  1. I read from the datasheet that

After the module VBAT is powered on, keep the RESET_N and BOOT high (default), and the module will turn on automatically

and

After VBAT is powered on, RESET_N and BOOT automatically rise to high level due to internal pull-ups.

Is it safe to assume no additional circuitry is needed to enable ‘automatic power on’?

  1. Is it possible to use TPS3823 to control RESET_N signal? Could I pulse watchdog pin on TPS3823 with a GPIO on BC660K-GL? What would the schematic look like?

  2. If the above is possible, what circuits should I add (if any) to allow for BC660K-GL programming mode? Would I need to somehow disable the watchdog IC (TPS3823) to prevent reset during programming?

Thank you!
Mike

2

@Jouni.yang-Q any comment on this question?

3

hi,Michael_Morena:
I suggest you refer to the attached document
BC660K SDK

4

@herbert.pan-Q Thank you for pointing me to this information. However, after quickly reviewing the documentation “BC660K-GL QuecOpen Hardware and Reference Design”, I cannot see even a single difference compare to the BC660K-GL standard set of documentation.

An example to explain this is (From BC660K-GL QuecOpen Reference Design)

image
image2215×807 98.1 KB

This reference design refers to an MCU application, which is contradictory to the purpose of QuecOpen, no?

My original questions 1, 2, and 3 from March 12th persist.

I understand that what I am describing might be considered application specific to the point where it cannot be supported with a simple forum question+answer, but I put these questions here because given my experience this will be very common questions when considered implementing BC660K-GL with QuecOpen.

5

Hi Michael,

I can answer your questions (if it’s not too late):

  1. Yes, module powers on without any external help.
  2. In theory yes, but there is a timing issue. The external watchdog may reset your module before it finish boot process. Usually the timeout is 1,6 seconds and boot process can take up to 2-3 seconds, depending on firmware. This result in an endless reset loop without a chance to finish the boot process. To avoid this, you must enable your watchdog after your app is started.
  3. I have no example code for you, but it is not too difficult to control an GPIO to control the watchdog.