This breakout board has a 10K resister and 22pf cap on it.
I'm just going to by the DS3234 chip alone, but I'm wondering if in my schematic I need those two components? They look like they might be used with the square wave pin or something? All I will do it connect the chip to my Atmega's SPI interface. So will I need the resister and capacitor?
thanks..
See the "Typical Operating Circuit" on the very first page of the datasheet. They show a bypass capacitor and a pull-up resistor on the INT/SQW pin. You should also include a backup battery.
Under pin descriptions it says:
"4 VCC DC Power Pin for Primary Power Supply. This pin should be decoupled using a 0.1?F to 1.0?F capacitor."
"5 INT/SQW Active-Low Interrupt or Square-Wave Output. This open-drain pin requires an external pullup resistor. It can be left open if not used. This multifunction pin is determined by the state of the INTCN bit in the Control Register (0Eh). When INTCN is set to logic 0, this pin outputs a square wave and its frequency is determined by RS2 and RS1 bits. When INTCN is set to logic 1, then a match between the timekeeping registers and either of the alarm registers activates the INT/SQW pin (if the alarm is enabled). Because the INTCN bit is set to logic 1 when power is first applied, the pin defaults to an interrupt output with alarms disabled. The pullup voltage can be up to 5.5V, regardless of the voltage on VCC. If not used, this pin can be left unconnected."
so in layman's terms, all I need is the battery, correct? I don't need the INT/SQW pin to connect this to SPI on my Atmega328? (I'm new to SPI)
The battery and the bypass capacitor.
You may have to also provide logic level shifting if your Arduino runs on 5V (as most do) and the clock chip can't stand 5V on inputs. Look in the datasheet for the range of acceptable Vcc voltage and the range of acceptable input voltage.
Yikes! I thought it would work with the UN
Cording to the data sheet the DS3234 will work with the UNO because the max voltage is 5.5 volts.
Am I correct on this?
Yes, it looks like it will run fine on 5V.