wireless problem

[az1]

hi..

currently i'm doing a project which uses a wireless card.. that wireless card operates with 0V-2.7V for both Tx and Rx pin.. for communication testing purpose, i interface that card with with MAX232 circuit, which i connect Tx pin to T2in at MAX232 and Rx pin at R2out as in the attachment..

the problem is, by using serial comm monitor, i didn't manage to send and receive the data.. according to the manufacturer, the card has been tested and working well.. besides, i did test my MAX232 circuit and it works well.. any ideas?

[zhenning]

hi..

currently i'm doing a project which uses a wireless card.. that wireless card operates with 0V-2.7V for both Tx and Rx pin.. for communication testing purpose, i interface that card with with MAX232 circuit, which i connect Tx pin to T2in at MAX232 and Rx pin at R2out as in the attachment..

the problem is, by using serial comm monitor, i didn't manage to send and receive the data.. according to the manufacturer, the card has been tested and working well.. besides, i did test my MAX232 circuit and it works well.. any ideas?

Of course. TX of the max232 should be connected to RX of the wireless card and vice versa.

[az1]

ops.. my drawing supposed to be as attached.. my Tx is connected to R2out and Rx is connected to T2in..

back to the problem, as my wireless card operates with 0V-2.7V, is there any issues for MAX232?

thanks..

[yonghui]

what is the wireless card ur are using? . are u sure the commands u sent to the wireless card is correct? are u sure that the wireless card can accept up to 3.3V?? u mentioned tat it operates up to 2.7V only? max232 can operate on 3.3V or 2.7V ??

[az1]

im using Wavenis Wavecard.. attached, a screenshot for wavecard pin.. the card operates max 4.5V input supply..

[zhenning]

im using Wavenis Wavecard.. attached, a screenshot for wavecard pin.. the card operates max 4.5V input supply..

The max232 requires 4.5V min to 5.5V max.

[az1]

by using 3.3V, i have tested my MAX232 circuit by connecting directly pin T2out to pin R2in and i send "ABC" and the i manage to receive "ABC".. from this testing, i understand that my MAX232 circuit works well..

[zhenning]

by using 3.3V, i have tested my MAX232 circuit by connecting directly pin T2out to pin R2in and i send "ABC" and the i manage to receive "ABC".. from this testing, i understand that my MAX232 circuit works well..

Did you try 2.7V voltage supply on the max232? Your tx and rx max is 2.7V.

[az1]

yes.. i did try supply 2.7V to MAX232 and it's not working for MAX232 circuit either with or without (jump T2in with R2out) Wavecard.. besides, i understand that MAX232 operates with 3V min.

[zhenning]

yes.. i did try supply 2.7V to MAX232 and it's not working for MAX232 circuit either with or without (jump T2in with R2out) Wavecard.. besides, i understand that MAX232 operates with 3V min.

Because max232 is not suppose to be use for 3.3v operation. Though, you can. Get MAX3223. Its a 3.3V device. It has something to do with the logic level. 2.7V in 3.3V TTL is consider high but, in 5V TTL its a different story. Do update us