ulrikp
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Hi,
I'm using a SIM900 module, and usually it works fine, but lately it has started giving the error "+CPIN: NOT READY". As soon as I get this message, the voltage on SIM_VDD drops to 0V. The problem is intermittent (i.e. it happens only sometimes).
It seems to happen more often on 3V SIM cards than on 1.8V sim cards. If it happens on a 3V SIM card, I can switch to 1.8V SIM card, and the problem is temporarily solved, and vice versa.
I have read all related posts on here. Here is some info on my setup:
-Schematics is designed according to SIM900 documentation.
-I use 6-pin SIM connector.
-Firmware is B10. I have tried with B11, and it makes no difference.
-Changing input power does not help. I have tried with up to 12V, 2A.
-Adding decoupling caps on SIM_VDD, on input power, and on VBAT (for SIM900) does not help.
-Signal strength is fine (about CSQ=20).
The "+CPIN: NOT READY" is sent at different times, however, often quite soon after power on. Below is a typical situation.
%%%%%%%%%%%%%%%
IIII
RDY
+CFUN: 1
+CPIN: READY
Call Ready
+CPIN: NOT READY
%%%%%%%%%%%%%%%
If it doesn't happen as above, I can often make the problem occur by trying to make a voice call ("atd nnnnnnnn;")
Can someone please help out?
Thanks!
Ulrik
I'm using a SIM900 module, and usually it works fine, but lately it has started giving the error "+CPIN: NOT READY". As soon as I get this message, the voltage on SIM_VDD drops to 0V. The problem is intermittent (i.e. it happens only sometimes).
It seems to happen more often on 3V SIM cards than on 1.8V sim cards. If it happens on a 3V SIM card, I can switch to 1.8V SIM card, and the problem is temporarily solved, and vice versa.
I have read all related posts on here. Here is some info on my setup:
-Schematics is designed according to SIM900 documentation.
-I use 6-pin SIM connector.
-Firmware is B10. I have tried with B11, and it makes no difference.
-Changing input power does not help. I have tried with up to 12V, 2A.
-Adding decoupling caps on SIM_VDD, on input power, and on VBAT (for SIM900) does not help.
-Signal strength is fine (about CSQ=20).
The "+CPIN: NOT READY" is sent at different times, however, often quite soon after power on. Below is a typical situation.
%%%%%%%%%%%%%%%
IIII
RDY
+CFUN: 1
+CPIN: READY
Call Ready
+CPIN: NOT READY
%%%%%%%%%%%%%%%
If it doesn't happen as above, I can often make the problem occur by trying to make a voice call ("atd nnnnnnnn;")
Can someone please help out?
Thanks!
Ulrik