Output after reset


#1

If I set up an output for HIGH level and then I restart module with reset or AT+CFUN=1, the output is beeing reset to LOW for a second or two and then it restores back to HIGH. Module q2686, GPIO13 (ROW4), firmware 6.63c AFAIR.
This behaviour is the same with started application and stopped. So I guess it is the problem of the module itself.

I need an advice, how I can make an output which does not reset during restart…


#2

check the pts (product technical specification) document for your product.
gpio 4-8 's reset state is pull-up(10k) to 1,8 v
the only gpio with a reset state to 2,8 v is muxed with rxd1

chapter 3.3 Electrical Information for Digital I/O
and 3.9 General Purpose Input/Output
should give you all the information you meed


#3

Try using AT+WIOM command for setting power on state of I/O pins


#4

oi… new commands :slight_smile:

but i don’t think that these will hold up over resets.
the states discribed in the product datasheet are valid during reset periods. whereas these commands even block your application from subscribing to the gpio’s the normal way (ie. via ADL)


#5

Ok. So what I should do to get the valid voltage level during reset? For example I use gpio4 and I set the output for HIGH. Will it remain HIGH during reset sequence? Maybe yes. So what about LOW level on the same pin?

BTW, WIOM and other related commands do not provide any help for this reason.


#6

simple answer…

You can’t.

This is hardware (or low level OpenAT software) set. There is no way to change that state. If you need a specific pin-state during reset you need to connect to the pin wich gives you that state.
The states of the pins are documented in the document i discribed below.


#7

Thank you for your answer.

It seems that wavecom modules are just useless for virtually every kind of applications, if used without some kind of host processor…


#8

You will find that any host processor has exactly the same question of what happens to the outputs after a hardware reset but before the software has had a chance to set them into their “normal” operational states.
(eg, it is a common quesion at http://www.8052.com)

The only solution is to read the datasheet first to find the output states at reset, and then design your hardware to work with that.


#9

Couldn’t find this question on your forum. But anyway I see a couple of flaws in wavecom design.
Why AT+CFUN is considered a hardware reset.
Why the reset sequence is so long - the reset value stays for 2-3 seconds.

You can stop adressing me to datasheet - I’ve already read it.


#10

AT+CFUN=1 performs a complete restart of the entire product - so it is equivalent to a hardware reset.

Because it’s a complete restart of the entire product - including the OS and the GSM stack.