Author Topic: How to Program a Dallas DS1245W? This is a 3.3V Device.  (Read 194 times)

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Offline calibrationfixtureTopic starter

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How to Program a Dallas DS1245W? This is a 3.3V Device.
« on: January 18, 2025, 02:06:10 pm »
Hi to All,

Contrary to the 5V Versions, my Batronix Programmer doesn't cover these 3.3V Versions. I could lower the Vcc with two Diodes in series and make the Vcc connection out of the ZIF-Socket. A legitimate solution? Thanks in advance for any insights.

Calibrationfixture
« Last Edit: January 18, 2025, 02:23:53 pm by calibrationfixture »
 

Online Ian.M

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Re: How to Program a Dallas DS1245W? This is a 3.3V Device.
« Reply #1 on: January 18, 2025, 03:00:24 pm »
No.  The datasheet says:
Quote
ABSOLUTE MAXIMUM RATINGS
Voltage on Any Pin Relative to Ground -0.3V to +4.6V
which means the address, data and control pins are *NOT* 5V tolerant.   If the programmer is using 5V Vcc with CMOS thresholds, it will overdrive the Dallas DS1245W pins.
 

Online coromonadalix

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Re: How to Program a Dallas DS1245W? This is a 3.3V Device.
« Reply #2 on: January 18, 2025, 06:06:43 pm »
@calibration

there was no need to restart a thread about your equipment,    your diluting the subject into many parts,   many are doing this nowadays  and it get really annoying to follow

just find a programmer for it

TL866A or CS,  TL866II,  Xeltec and others can do it,  arduinos projects can do some of them etc ...
« Last Edit: January 18, 2025, 06:09:16 pm by coromonadalix »
 

Offline DonKu

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Re: How to Program a Dallas DS1245W? This is a 3.3V Device.
« Reply #3 on: January 18, 2025, 06:31:22 pm »
No.  The datasheet says:
Quote
ABSOLUTE MAXIMUM RATINGS
Voltage on Any Pin Relative to Ground -0.3V to +4.6V
which means the address, data and control pins are *NOT* 5V tolerant.   If the programmer is using 5V Vcc with CMOS thresholds, it will overdrive the Dallas DS1245W pins.

If you have the time, it's fairly easy to construct a DIY bi-directional voltage level shifter:

« Last Edit: January 18, 2025, 06:34:26 pm by DonKu »
 

Online Ian.M

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Re: How to Program a Dallas DS1245W? This is a 3.3V Device.
« Reply #4 on: January 18, 2025, 07:44:54 pm »
True, but will a simple discrete MOSFET level shifter be fast enough for a programmer running a RAM chip definition, that wont have any extra delays?

Its probably easier to breadboard a dedicated 'burner' using any 3.3V Arduino with enough I/Os.
« Last Edit: January 18, 2025, 07:47:15 pm by Ian.M »
 


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