Hi, I am interfacing 8051 with SIM300CZ. SIM300CZ has serial interface through which 8051 gets connected and sends AT commands. SIMCOM's serial interface works on TTL logic and 8051 also works on TTL logic so not using level converter. I need the details of handshaking signals required to write my program for 8051. I need the voltage level details for DCD, DTR, RTS, CTS, RI pins so that I can use GPIO pins of 8051 for handshaking.
Please elaborate the serial handshaking pattern so that I can write my code for handshaking accordingly.
Fast response is required & appreciated.
Rgds Sam
"I need the details of handshaking signals required to write my program for 8051." 8051 data sheets and Keil toolchain manuals lack those details. What does the SIM300CZ documentation say?
"I need the voltage level details for DCD, DTR, RTS, CTS, RI pins so that I can use GPIO pins of 8051 for handshaking.'
The voltage thresholds should be documented in the data sheet for the particular 8051 you are using and likewise for the SIM300CZ.
"Please elaborate the serial handshaking pattern so that I can write my code for handshaking accordingly."
Not surprisingly SIM300CZ handshake patterns are are entirely lacking in Keil toolchain manuals. Language toolchains are unconcerned with matters of serial handshaking.
"Fast response is required "
Oh, I'm glad I have not been negligent in fulfilling my required duty to you.
I think that it is required that you read up on RS232 communication. The singnals are standardized and should behave the same if used on a microcontroller or on a PC.
The only think is that the microcontroller talks TTL levels and depending on what you connect to your microcontroller you may need a RS232 transceiver or 3.3V to 5V level converters or similar to make the two sides electrically compatible.
Hi, Well, SIM300CZ datasheet does not provide any details for handshaking or the voltage level details. Can you provide me the sequence in which the handshaking signals(DTR, RTS, DCD, RI, CTS, etc) works so that I can follow the same and implement in 8051 using the GPIO pins.
Sam
What do you think a normal modem does with the handshake signals? They are not specific to a particular chip. There are tons of information out there about these signals. That is probably also why the datasheet doesn't spend time on describing the signals.
If the chip uses TTL levels for the signals, then the datasheet probably do contain information about the voltage levels. It's just that they don't explicitly mentions these signals but describe the general voltage levels for all digital inputs and outputs.
Provide me the sequence of these signals and I can make the thing run.
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