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 on: Yesterday at 06:47:36 PM 
Started by zuisti - Last post by zuisti
The newest update of my RTC project is the "Multi-Alarm Clock", that I want now to show.
Here are the new features (but also look at my previous posts) :

- three independent daily alarms (a-b-c), choosable displaying
- alternating date and temperature display (can be off)
- button sounds (acoustic feedback, can be off)
- the settings are valid until power-off but can be stored
- forced cold start (without battery detach):

    set the C alarm to 00:00, it is working fine until
    power-off, but the next power-up produces a cold start.
    Alarms A or B work well at 00:00 also, so use them if
    you really want to wake up daily at midnight :-)

It works well with Ds1307 and also the Ds3231M (see photos), using the same HEX.
This HEX is also used by the included Proteus simulation, which shows the treatment
in detail (see GIF images). This way you can test the Clock without building it, so
I'm looking forward your valued comments and advices.


The circuit was built on a breadboard, using cheap chinese modules I bought on Aliexpress:

16x2 I2C LCD module (using a PCF8574 I2C 8-bit port-expander backpack)
Its I2C address is 0x4E (in 7-bit form: 0x27), fixed: A0..A2 tied to VCC

RTC modules, using a 3.6v LIR2032 accu (just one RTC module is used at a time :-)
- "ZS-042" RTC module (mine is Ds3231M, unfortunately)
- Tiny RTC I2C module (Ds1307)

An experience with the Tiny RTC module:
 Due to the 3.6v accumulator, the "original" Ds1307 module uses a high-impedance
voltage divider, that makes it susceptible to interferences and can cause startup
problems. A small filter capacitor (47-100nF) on the BAT terminal solves this problem.
 Or - modify the module (in a way that can be found on the net) to be use a 3v CR2032 coin cell.
But .. due to my weak vision (I'm 75) I didn't do this.

The Ds3231M is less accurate, but has an advantage also: it updates the temperature
registers every 10 seconds while the Ds3231SN only every 64 seconds.

PS: Sorry for the bad quality photos ..

 on: Yesterday at 02:29:37 AM 
Started by Just4Fun - Last post by Just4Fun
Just to complete the info, as suggested by h0nk, I've made a new test on a new board without the EPCS4 eeprom soldered.

But the behavior was the same... at compile time all seems ok, but anyway the ASDO pin didn't work as an IO pin ... (using JTAG to program the configuration).

So or there is a "bug" in Quartus II (v13sp1), or when MEMSEL0/1 are set in the AS/JTAG mode (both LOW. See the attachment in my first post) the ASDO pin can't be used as IO in any case (and the datasheet is not clear about this...).

 on: February 17, 2019, 02:08:58 14:08 
Started by allame - Last post by allame
NoteElectric & Electronics Engineering Student
Enthusiast ARM programmer

 on: February 16, 2019, 04:04:53 16:04 
Started by max - Last post by Checksum8
If you can't get the Xicor to work, take a look at the MCP41HVX1. It's specified for up to +36v or +/-18v. Page 24 of the data sheet shows the different digital ground configurations. I bought some samples, but have not had the time to test them out.

 on: February 16, 2019, 02:30:47 14:30 
Started by max - Last post by PICker
Hi, I've worked for a long time with Digital potentiometers for designing custom gain instrumentation amplifiers/signal subtractors.
The main issue is the wide range of resistance variation among chips while the laser-trimmered R values inside the single device is amazing.
This make a DIGIPOT useful for creating analog Resistor nets for operational amplifiers with low % differences inside the chip.
Another problem, I rembember, was the difference with real potentiomenters about bipolar signals in relationship with the power supply of the DIGIPOT. Some devices are exclusively for single supply applications while others for dual supply.
Just for having an idea and if you have time, read the following introductive document from Analg Devices:

 on: February 16, 2019, 01:13:13 13:13 
Started by max - Last post by jumulab
take a look this data book from Xicor.

 on: February 15, 2019, 10:25:12 10:25 
Started by philmit - Last post by philmit
Thank you for invitation. Registration is done.

Note: This message sent by the system behalf of philmit.

 on: February 15, 2019, 07:18:06 07:18 
Started by aiantas - Last post by aiantas
NoteI am an electronic engineer with more than 10 years experience in Embedded C Programming (ARM,  PIC), Analog and Digital Hardware Design,Delphi, Proteus. I am willing to help and to share my knowledge and
when I need to get advice and help.

 on: February 15, 2019, 06:32:59 06:32 
Started by SpaleKG - Last post by yxpsv
NoteThe electronics are my hobby and we are working with amateur programming AVR, Arduino

 on: February 14, 2019, 04:48:58 16:48 
Started by nullos - Last post by kreutz
@ kreutz:  Why you don't ask the vendor? Actually only they should know. Also this question is kind of off-topic. If you need anything particular, find the appropriate discussion and ask. Believe this place is not exactly here.

AFAIK the thread's title is "CCS".  Here we are supposed to discuss CCS issues and all questions are on topic. This thread is not to just download attachments.

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