ST7537 Help

[joc]

Posted on June 03, 2004 at 08:54

ST7537 Help

[joc]

Posted on June 02, 2004 at 21:36

Hello all,

My name is John and i am new here I was wondering if you could give me a little help with a project im doing on powerline communication? I bought a few of the ST7537 chips and got the datasheet and am in the process of making up some pcbs but i cant seem to source the toko t1002n transformers needed/referred to in the data sheet. Has anyone around europe bought these or know a supplier. i ordered some from an italian crowd but heard nothing since so... Also the data sheet isnt clear cut as to how many pins i need to use on the rs232 port. You see im trying to use an avr to replace the pc in the schematic on the data sheet so can i just go rx--tx and tx--rx or do i nned to set or clear other signals?? Also what the test pins 10 to 14 used for? Will i just tie them low? Any help would be greatly appreciated. Thank you Regards John

[sjo]

Posted on June 03, 2004 at 08:54

John,

Have a look at P2824 from Etal (now called profec), this transformer also has approvals whereas a lot of others do not. Regarding the RS232, all you need to use is pin23,22,20 - don't forget to refresh watchdog though. CD is set low when data is has been received by the plm. reception can be improved by clamping TXD pin to Vss during receive. Have a look at the following appnotes for details: http://us.st.com/stonline/books/pdf/docs/1751.pdf http://us.st.com/stonline/books/pdf/docs/1124.pdf http://us.st.com/stonline/books/pdf/docs/3724.pdf pins 10-13 are normally tied to Vss, pin 14 to Vcc. Have you thought of using the newer st7538 ? Regards sjo