Hello,
I work with an controller (with two crystals - 32.768kHz and 18.432MHz). When the controller starts only the 32.768kHz crystal is working - the main crystal is only working if I turn it on by software.
At the moment I've no main crystal - only the 32.768kHz crystal installed; if I download some code to the internal memory I use for the "max. JTAG clock option" 1MHz - what is the relation between this Jtag clock and the crystal from the controller? I've thought, that I'll not be able to store some code within the controller with a higher frequency then the crystal is running...
best regards Scott Alan
thanks for your reply... could you imagine what would be the problem for the low AC voltage at the crystal? The frequency is correkt and I'm able to download some code into the internal RAM, but I never saw such a low AC voltage... the DC voltage for the crystal is 240mV (which should be enough)...
I've tested a few crystals - always the same result.
best regards Alan Scott
Does Atmel have any document about how hard they drive the crystal?
I assume that the chip has support for very, very, very low power consumption running with the clock crystal.
could you imagine what would be the problem for the low AC voltage at the crystal? 1) 32 kHz crystals are tricky 2) based on comments on the latest '51s from Arghmel, Arghmel has 'forgotten' how to make good oscillators. 3) Keil forum is really not about oscillators and such, but about the Keil tools, there is a therad in an appropiate forum www.8052.com/.../read.phtml regarding making 32kHz xtals 'sing'.
Erik
I spoke with atmel too, but they said that the AC voltage must be higher than 50mV - they could only say that the DC voltage is ok for the 32.768kHz crystal.
I only ask in this forum, because maybe everyone of you has the same error in one of your earlier implementations of atmel chips e.g....