IR (SIR) UART 8051

@Paul
The method outlined by Ajay(receiving data through tsop connected to rx pin) would work well between 2 compatible uart interfaces(like 2 8051's or between a 8051 and pc serial port) but not with a 8051 uart and a SIR interface.

A SIR frame is totally different from the 8051's uart frame....different timings,diff start/stop bits,different payload length,a high baud rate(115200) etc.

So you have 2 options...
use sth like max3100 to translate between the 2 interfaces
or use your own protocol for communication,in the lines of what I had mentioned earlier in some other thread of your's.

Hi SJ,

^It's the same thing....Ajay meant ANDing the tx pin with a square wave carrier,be it from a 555 or a pwm pin of the micro....

need some clarity here, i feel we can AND Tx pin with Vcc (logic 1) that is by connecting Tx to one input of an AND gate like 74LS09 and VCC to the other input and the output of the gate to Reset pin of 555 IC. the 38Khz from 555 will be given out only when Tx is high (logic 1)

on the other hand are you suggesting that Tx and 38Khz from 555(or PWM) be ANDed
thru a AND gate and IR LED connected to the Gate's output ?



Arun

i meant this

(TX out signal) AND (38Khz carrier) ---> Modulated signal as simple as it gets

Great guys...

Don't worry I'll be talking like that .... someday

Good, but still feels like on the first step of Embedded. But you guys are great supporters.

Keep the spirits up!!

need some clarity here, i feel we can AND Tx pin with Vcc (logic 1) that is by connecting Tx to one input of an AND gate like 74LS09 and VCC to the other input and the output of the gate to Reset pin of 555 IC. the 38Khz from 555 will be given out only when Tx is high (logic 1)

Hi Arun,
Doesn't make sense this way...may as well connect the TX directly to the 555 reset like you had mentioned.
Or else you could hardwire the reset to continuously produce 38k and then AND this to the TX pin so that an output(38kHz) is produced only when TX is high.