8051 + AT commands using Nokia phone

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nokia 1600 at command guide

Thanks a lot Budhy, I'll try it out and hope to get it done, the 8 lines are 8051 interfacing with IR sensor, nothing much to be concerned about, anyway thank you and sorry for inconvenient caused to you.

Added after 46 minutes:

Wait0DH:
ACALL SerialIn
CJNE A,#0DH,Wait0DH
RET

SerialIn:
JNB RI,SerialIn ;Wait for another character
MOV A,SBUF ;Save it in accumulator
CLR RI ;Get ready for next character
RET
Click to expand...

This means I have to receive 0DH instead of the letter 'O' and 'K'? I thought I have to receive an 'OK' from phone?
 

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Sorry but I have another question to ask: I've tried out the program but the phone still couldn't send out SMS, the question is I've measured the voltage drop at pin 10 and pin 11 which is RxD and TxD respectively, but I obtained 0V, is this possible? Shouldn't it be something around 5V?
Another question is that for the capacitors linked with crystal and pin 18 & 19, what value of capacitance shall I use? I've tried 12pF and 33pF but none of them worked.
 

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This means I have to receive 0DH instead of the letter 'O' and 'K'? I thought I have to receive an 'OK' from phone?
Click to expand...
Code: 
;; ***** you don't need to execute the following 4 lines every time
;
     MOV   DPTR,#CMGF
     ACALL SingleCommand
     MOV   DPTR,#CSCA
     ACALL SingleCommand
Do it once from HyperTerminal, and don't worry about OK etc...

Another question is that for the capacitors linked with crystal and pin 18 & 19, what value of capacitance shall I use? I've tried 12pF and 33pF but none of them worked.
Click to expand...
Normally use 33 pF. Powered your uC then use Osciloscope to check your curcuit, if there is clock stream on ALE (pin #30) it means your circuit is OK.

I've measured the voltage drop at pin 10 and pin 11 which is RxD and TxD respectively, but I obtained 0V, is this possible? Shouldn't it be something around 5V?
Click to expand...
Are you sure there are 5 Volt on pin 40, and pin 20 connected to ground?
 

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Are you sure there are 5 Volt on pin 40, and pin 20 connected to ground?
Click to expand...

Yes, I've measured pin 40, it's 5V, pin 20 is ground, but the RxD and TxD values are very low, what voltage should RxD and TxD have?
 

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Refer to your diagram,

there are two reason can cause the volatge on pin 11 (TX) of 8051 about 0 Volt:
1. No Voltage between pin 20 and 40 (please measure again directly at that 2 pin)
2. Your 8051 chip is out of order

there are two reason can cause the volatge on pin 10 (RX) of 8051 about 0 Volt:
1. that pin not connected to phone TX
2. Your phone is out of order

At this two lines at top of your program before doing above testing
Code: 
     SETB P3.0
     SETB P3.1

Do you already test the ALE signal?
 

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At this two lines at top of your program before doing above testing
Code:

SETB P3.0
SETB P3.1
Click to expand...

That means I insert these 2 lines and connect the circuit without connecting the phone? Or with the phone? I thought port 0,1,2 and 3 are all high in default? So I still have to set P3.0 and P3.1?

Do you already test the ALE signal?
Click to expand...
Not yet, the lab is not open these few days because of public holiday, going to test it out later.

Added after 1 minutes:

P/s: What voltage should it be on TxD and RxD? Should they be 5V?
 

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That means I insert these 2 lines and connect the circuit without connecting the phone? Or with the phone? I thought port 0,1,2 and 3 are all high in default? So I still have to set P3.0 and P3.1?
Click to expand...
Yes, you are right. Those 2 lines just for make you sure RX and TX is at high states

Test with two condition, with and without the phone

What voltage should it be on TxD and RxD? Should they be 5V?
Click to expand...
The stand by state of serial transmission line is 'high', so TxD should be around 5 Volt

RxD is prepare for input (you already set RE - Receive Enable bit), so RxD should be around 5 Volt

I doubt your uC chip is out of order
 

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I will try it out again when lab reopens, anyway thanks for your help and Happy New Year to you.
I will post my problem again if I meet any.
 

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I have another problem over here..
I've added an LCD to be interfaced with the AT89S51, but then the output voltage of the 89S51 pin is just 1.8V instead of 5V, which is very very low to run the LCD, why does this happen?
By the way, what is the difference between AT89S51 and AT89C51?

Thanks in advance.
 

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Just pull up the pins of the 89S51 and you should be fine. What voltage is the 89S51 operated on.
 

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What do you mean by pull up the pins of 89S51? It operates on 5V, and should output 5V as well.
 

nokia 1600 atcommand

The output of 8051 (both C51 and S51) is not a push-pull type output. It is a weakly pulled-up open-drain type output. It can sink large currents (5ma or so) but can source only a few micro-amps. So if you feel that the output is not capable of driving properly, you connect about 4.7kohm resistors between the port pins and +5V.
Alternately, you can use a 74LS244 type buffer.
I have not found much difference between C51 and S51 as far as port pins are concerned.
 

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dancingqueeneng said:
What do you mean by pull up the pins of 89S51? It operates on 5V, and should output 5V as well.
Click to expand...
wat port are u using?
P0?
 

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But as far as I concerned, the port 1, 2 and 3 are already pulled up internally, do we still need to pull them up externally?

P/s: I'm using port 1
 

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As I said earlier, the pullups are very weak. About 50kohm internal pullups. If the output need to drive something that requires more current, you need to pullup like you do on P0.
 

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I've added an LCD to be interfaced with the AT89S51, but then the output voltage of the 89S51 pin is just 1.8V instead of 5V, which is very very low to run the LCD, why does this happen?
Click to expand...
the 1.8 V pin voltage is measured before or after AT89S51 connect to LCD module?
What is the voltage before connect AT89S51 to LCD module?

By the way, what is the difference between AT89S51 and AT89C51?
Click to expand...
At this case, AT89S51 and AT89C51 are totally compatible.
 

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the 1.8 V pin voltage is measured before or after AT89S51 connect to LCD module?
Click to expand...

1.8V is measured after it is connected to LCD.

As I said earlier, the pullups are very weak. About 50kohm internal pullups. If the output need to drive something that requires more current, you need to pullup like you do on P0.
Click to expand...

I will test it out tomorrow, thanks for helping.
 

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