My questions related to EC20 are as follows:-
1] Does EC20 have an inbuilt RTC?
(The EC20 hardware manual does NOT mention at all about inbuilt RTC. Also EC20 block diagram does NOT
show a RTC block. So I want to know whether EC20 has an inbuilt RTC or not?)
2] If EC20 does have a inbuilt RTC, then does it have a pin similar to VRTC pin of M66 (so that battery backup
can be provided only to the RTC section of EC20) ?.
Reason for having these questions:-
In our existing product, we have used the M66 module (which is 2G).
We want to replace M66 with a 4G module (either EC20 or EC200-U).
Presently we rely completely on inbuilt RTC inside the M66 for getting local time.
We have provided coin-cell battery backup to VRTC pin of M66 to retain the local time even if power to M66 fails. We want to retain this feature in new design, that shall use EC20 instead of M66.
That is why I want to know, whether EC20 has a inbuilt RTC and does EC20 have a pin that can be used to provide battery backup to the inbuilt RTC ?
Hello MBR
The RTC function of EC20 is integrated in the PMIC and there is no separate RTC pin; RTC is connected to VBAT_BB inside the chip, so VBAT_BB cannot be powered off when using the RTC function, and EC20 cannot use coin batteries for time backup, thank you.
Hello Duncan.Xu-Q,
I need a reference schematic of EC20.
It will be nice if I can get the schematic of EC20 evaluation board.
I will use it as reference while making changes in my product schematic in which I am replacing M66 with EC20.
Thank you.
Hello Duncan.Xu-Q,
Thankyou for sharing the above link.
Instead of EC20, I have decided to use EC200U.
I have a query which is as follows:
EC200U has a main antenna and a wifi/bluetooth antenna.
What should be the minimum distance between the antenna connectors-
(actually mounted on the PCB) for these antennas (i.e. main antenna and a wifi/bluetooth antenna)?
Please find attached, the image of SMA type antenna connectors that I will be using on the PCB.
The EC200U datasheet only mentions that “proper distance” should be ensured but does not mention/specify the minimum distance between the antenna connectors.
Thank you.
Hello Duncan.Xu-Q,
Thank you for a quick reply to my earlier query.
I have some more queries about EC200U network registration status indication pins, which are as follows:
With ref. to a modem IC (like M66 or EC200U) what is the difference between the terms-
“module Synchronized with network” and “module Registered on the LTE network”?
The reason why I am asking this question is because, I want to know whether, just the-
‘NET_MODE’ pin of EC200U can be used to identify whether the module is Registered on the network or not.
EC200U has one more pin ‘NET_STATUS’ which specifically indicates the modules ‘network Registration status’.
So if ‘NET_MODE’ pin serves both the purposes then I can decide whether or not to use ‘NET_STATUS’ pin for indication LED or to just go with just one ‘NET_MODE’ indication LED.
Please refer the attached screenshot from the EC200U datasheet.
When the ‘NET_MODE’ is flickering quickly, it means network status is ‘idle’.
So does this ‘idle’ network status mean that module is neither searching the network and nor is any data transfer going on but the SIM is registered on the network?
Please inform.
Thank you and Best Regards,
Milind.
Hello there,
You can judgement the status of network by the ‘NET_MODE’ LED, but we suggest you can use ‘NET_STATUS’ as well. When the ‘NET_MODE’ is flickering quickly, it means network status is ‘idle’, this ‘idle’ network status means UE has registered the network but no data transmission.
Hello Duncan.Xu-Q,
Thankyou for confirming that: The NET_MODE pin flickering quickly-
is an indication that the module is registered on the LTE network.
Also thankyou for a quick reply.
Best Regards,
Milind.
I am ready with our prototype unit that has EC200U in it.
My existing firmware (for unit with M66) runs as it is in this new unit.
While testing this new unit I am facing a problem which is as follows:-
When a SMS is sent to the unit, the EC200U does not send a URC to the microcontroller.
Because of this the microcontroller does not come to know that a new SMS has arrived and so does not read it.
By default the URC is enabled in EC200U, but still this is happening. I don’t know why.
I tried giving relevant commands like AT+CNMI=3,1 but it has been of no use.
Please help in resolving this problem.
Thankyou,
Best Regards,
Milind.
