AUTO WAKE UP ON ST7LITE

[mirko2]

Posted on May 12, 2005 at 06:13

AUTO WAKE UP ON ST7LITE

[mirko2]

Posted on May 05, 2005 at 04:16

hi to all,

I have a questions to you. I have to implement a HALT function on our ST7 lite19 and I have choise AWUFH mode. We have a Internal RC to 8MHz with LiteTimer RTC1 Interrupt every 1mS. I haven't understand how I can obtain the tAWU period: • on the formula I don't catch who is fAWURC and tRCSTRT. • I haven't understand so well, how I can calibrate the AWU RC oscillator (If I set it in run mode? AWUM, the fAWU_RC is connect to 12-bit AutoReload Timer that give me an interrupt? So I can measure the time between the set and the interrupt event?? ) There are some Application note about this subject ?? Many tanks mkbs :-[

[anshul]

Posted on May 09, 2005 at 07:36

You need to first measure the fAWURC. The measurement mode can be eanbled by setting the AWUM bit. As you measure the frequency of any signal using Input Capture similarly you measure this frequency. Then as you have this frequency now you can calculate AWUPR value using the formula on page 45 for the desired value of tAWU.

The value of tRCSRT is mentioned on in table 13.5.5 i.e. a maximum of 50usec.

[mirko2]

Posted on May 10, 2005 at 04:32

Many Tanks Ansh !!!

:-] :-]

[mirko2]

Posted on May 12, 2005 at 06:13

Sorry,

I,m little confused... I have set AWUM and I have tryed to capture ATICRL and ATICRH every 1ms but the ATICR register value was 0. Perhaps,Have I to generate an external interrupt on Pin ATIC to achive the correct value ?? If isn't possible to generate an external interrupt is possible to measure this frequency (fAWURC)? mkbs :-?