Topic : RC Oscillator Control Byte OPT for 12 MHz external clock

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February 18, 2010 - 5:52pm Guest	Hi, I need to change oscillator control registers from internal 630KHz to external OSC 12 MHz. I couldnt do that only with the R-Link v3.4 and your REva 2.10 because it use the ICC interface :mad: I debug code, but only processed at 630 KHz :/ If I program a IC on the ST7SocketBoard (like the ST7SB10-123) with your R-Link v3.4 that I already have, could I change OSC to take the external waveform? Have you got other solutions? I need F-OSC 12 MHz to achieve F-CLK 6 MHz... Thx ;)

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+1 0 -1 February 19, 2010 - 9:19am Raisonance Support Team	Hi, I'm not sure I understand what you are asking, but I'll try to give you some hints... First, check in the RLink options that you instruct it to program the option bytes, and that you give them a value that tells the ST7 to work on external oscillator. Then you need to provide _one_and_only_one_ clock to the ST7... If you want to use the 12MHz clock from the RLink to clock the target, ST7, then you must check that the 12MHz jumper is plugged. With RLink 3.x it is on the ICC ADP. With RLink 2.x it is one of the four jumpers that the doc says to plug when connecting to ST7. That will send the 12MHz from RLink on pin 9 of the ICC connector, as specified in the ICC spec. Then check on the target board that there is no other clock that would interfere with this signal. On the opposite if you want to use the clock from the target board, then you must remove this jumper, because if you keep it you will have two clocks that will interfere. I hope it helps. Best Regards, Vincent
+1 0 -1 February 22, 2010 - 11:05am Guest	VincentC wrote: First, check in the RLink options that you instruct it to program the option bytes, and that you give them a value that tells the ST7 to work on external oscillator. 1- 12 MHz jumper was ok. 2- RLink-Osc1 jumper was ok. 3- Now I changed "option bytes" 0xD0EF to 0xD0FF as you tell and all is perfect! Thank you, Vincent. PS: so I understand that data sheet mean: "Internal RC oscillator adjustment" bytes (RCCR: page 23) are not changeable through ICC... but it's quite possible to change "Option Bytes" (OPT: page 161). My bad =)