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duyha
Joined: 19 Aug 2009
Posts: 6
Location: VN
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 19 Oct 2009 4:15 PIC16F877A and SIM300CZ problem connection |
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Dear all,
please help me.
I used PIC 16F877a to send and read SMS via SIM300.
Serial connection:
PIC_TX -> SP3238 -> SIM300_RX
PIC_RX <- SP3238 <- SIM300_TX
Sim300_RTS -> GND
I read/send SMS via SIM300 OK but I send SMS -> Read SMS -> Read SMS(fail)
I don't read SMS again after send SMS. You can help me.
Thanks.
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duyha
Joined: 19 Aug 2009
Posts: 6
Location: VN
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21 Oct 2009 3:58 Re: PIC16F877A and SIM300CZ problem connection |
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Dear All,
I add information of connection between PIC and SIM300, please help me.
I connected SIM300_RTS -->GND, baud rate of of SIM300 are fixed 9600, PIC_UART baud rate are 9600
Thanks.
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fiolin
Joined: 22 Jul 2009
Posts: 27
Location: Uruguay
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21 Oct 2009 16:09 PIC16F877A and SIM300CZ problem connection |
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| Visit this topic http://www.edaboard.com/viewtopic.php?t=366904&highlight= and download the file called serial_port.pdf. May be can help you.
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duyha
Joined: 19 Aug 2009
Posts: 6
Location: VN
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22 Oct 2009 3:19 Re: PIC16F877A and SIM300CZ problem connection |
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Thanks for your reply.
I connected same as schematic in Serial_Port.pdf.
Current i send AT command (AT+CMGR=1) to read sms from PIC16F877A, i receive response of SIM300 but this response is not same as specification in file "SIM300C AT.PDF" , "item 1.4" page 5, i receive AT command read (AT+CMGR=1) in top of buffer (buffer store SMS in PIC16F877A).
Detail:
- send from PIC16F877A
AT+CMGR=1\r
- wait to get response from SIM300
- content of buffer after get response
AT+CMGR=1\r\r\l+CMGR: "REC READ"\r\lSMS_content\r\l\r\lOK\r\l
specification in file SIM300C AT.PDF, response must be:
r\l+CMGR: "REC READ"\r\lSMS_content\r\l\r\lOK\r\l
I don't know why i get "AT+CMGR=1\r" string in buffer, I try with another command, the result is same. You can explain?
Note: i have a sms in Sim card.
After i read SMS, sent SMS OK, i read SMS again fail, please help me.
Thanks
duyha
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22 Oct 2009 3:19 Ads |
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hoodooman
Joined: 28 Mar 2007
Posts: 1
Location: Italy
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22 Oct 2009 7:59 Re: PIC16F877A and SIM300CZ problem connection |
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I think you have echo mode active.
Disable it with ATE0.
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duyha
Joined: 19 Aug 2009
Posts: 6
Location: VN
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23 Oct 2009 2:24 Re: PIC16F877A and SIM300CZ problem connection |
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Dear hoodooman,
I sent AT0 command, it is OK, thank you very much.
Regard.
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angel_eyes
Joined: 12 Jan 2009
Posts: 14
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24 Oct 2009 7:33 PIC16F877A and SIM300CZ problem connection |
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| Have you sent at command "AT+CMGF=1" yet?
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duyha
Joined: 19 Aug 2009
Posts: 6
Location: VN
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26 Oct 2009 4:14 Re: PIC16F877A and SIM300CZ problem connection |
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Dear Angel_eyes,
I sent AT+CMGF=1, and store this setting in flash of SIM300C, I send and receive SMS OK.
Regards.
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tdma
Joined: 29 Oct 2009
Posts: 5
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29 Oct 2009 2:29 Re: PIC16F877A and SIM300CZ problem connection |
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| Is that an RS232 transceiver you have there? Is it absolutely necessary? You could just use open drain buffers with pullups.
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duyha
Joined: 19 Aug 2009
Posts: 6
Location: VN
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30 Oct 2009 2:25 Re: PIC16F877A and SIM300CZ problem connection |
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| I use LJ245A to convert logic level between PIC16F877A and SIM300.
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