michal
Joined: 07 Jan 2009
Posts: 2
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Posted: 08 January 2009, 2:43 AM Post subject: lower voltage operation of ZX24 (@3.6V) |
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Hi,
Could a 3.6V be used with ZX24 modules? (at room temp)
The ATmega644 spec shows max clock vs supply voltage and it appears at 3.6V it should still run at about 15MHz.
One would need to bypass 78L05 perhaps and if clock is still too high perhaps changed the cristal (say go to ~13MHz?)
I have read older post here on a similar topic but w/o firm conclusion.
Any ideas?
Thanks,
Michal |
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dkinzer
Site Admin
Joined: 03 Sep 2005
Posts: 2499
Location: Portland, OR
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Posted: 08 January 2009, 3:09 AM Post subject: Re: lower voltage operation of ZX24 (@3.6V) |
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| michal wrote: | | Could a 3.6V be used with ZX24 modules? (at room temp) |
Yes, a ZX can run as low as 3.55V according to Atmel specifications when operating at 14.7456MHz.
| michal wrote: | | if clock is still too high perhaps changed the cristal (say go to ~13MHz?) |
The operating frequency of a ZX cannot be changed. It must run at 14.7456MHz. Otherwise, nothing that is timing related (serial ports, RTC, PulseOut(), Delay(), etc.) will work properly.
| michal wrote: | | I have read older post here on a similar topic but w/o firm conclusion. |
The topic has been discussed before and my replies have been quite explicit. See, particularly, the thread at the link below which includes discussion of the minimum operating voltage. I know of people that have operated the ZX at 3.3V. It seems to work generally but you cannot reliably write to Flash memory at that voltage. This means, in particular, that with VM devices you can't update the firmware reliably and with native mode devices you can't download programs reliably.
http://www.zbasic.net/forum/about970.html |
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