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In my project i want to interface a GSM modem and 24c02C i.e EEPROM (I2C based)to microcontroller. so now i am not understanding whether can i use same Rx-Tx pins to interface microcontroller (89s52) to EEPROM and GSM modem as well?? if not then is there any other microcontroller of AT89cxx/AT89sxx family with 2 serial ports? and which will support embedded c and assembly too!
yeah but the problem is that if i use 89s52, then i shall be connecting EEPROM (I2C based) to Rx-Tx pins.. and data will be continuously read and written from and to respectively EEPROM. But i need to connect a GSM Modem also which will also need Rx-Tx pins..
So better i should use a controller with 2 UARTs..
Am i making any mistake?
Why would you connect an I2C device to the RX and TX pin of an UART? A UART is not designed to communicate with an I2C device. An I2C device has data and clock. Not RX and TX. It is a synchronous serial interface, while a UART implements an asynchronous serial interface.
Buy a processor with 100 UART and that will still make you happy if the processor doesn't also have I2C support. I2C != UART != SPI != Ethernet != USB != ...
ohk! now i am getting you:)
what EEPROM? if 24.... you can NOT use the UART Erik
can you please elaborate?
Can i get your e-mail ID?
Please :o
NO, the popurpose of a forum is that everybody learns
ANSWER THE QUESTION
what EEPROM?
Erik
ohk.. sorry!
Well.. This is the link which i was referring.
www.electronicsforu.com/.../view_article.asp
Here EEPROM is connected to Rx-Tx pins.. :o
That link is just 1 part of my project.
In 2nd part i am going to interface a GSM modem to controller. (Serially)..
So that Whenever bike exceeds a particular speed limit a message will be sent to predefined number..
in a way yes, but actually no
the pins, in this case are not used as Rx and Tx, but as regular port pins.
connect your EEPROM to two other pins, preferably those used for hardware I²C by a better chip than the one you have chosen. Based on the impression of your abilities your confusion gives me, I will not recommend that you tackle bit-banged I²C
ohk :)
a better chip than the one you have chosen
can you please suggest me a better one?
can you please suggest me a better one? sure, but why limit it to one
basically any chip that has been introduced the last 3 or more years from any '51 uC vendor (except AFAIK Arghmel) SILabs, NXP, ....
okay:)
but there are many chips and most of them are having some extra functionalities :o
can you please tell me which will be best suited for my requirements??
i.e. it should support I2C, 1 UART for GSM modem.. and 8051 features..
Here: http://www.keil.com/dd/search_parm.asp
It's pretty well hidden these days, but I found it here: http://www.keil.com/c51/chips.asp
I would strongly suggest that you get a chip with at least two UARTs - since one will be occupied by the GSM, you should have another free for debug purposes.
(The parametric search lists 104 with I2C + 2 UARTs)
And, if you're considering adding GPS at a later date (which is a very common next step), then get a chip with at least 3 UARTs...
... UARTs ...., you should have another free for debug purposes. unless you are smart and get a chip with JTAG debug