I am having a problem with Pierce oscillator designed to work with my SMART Card reader. I am using 3.58MHz oscillator, 74HCU04 gate IC for the NOT gate, and both 22pF capacitor and 1Mohm resistor. I was unable to get any clock pulse.
Pierce oscillator issues
oscillator
Related Solutions
Your start up sequence is wrong.
The correct procedure is:
- Power the card AND apply clock while reset is low
- keep reset low for at least 40000 clock cycles
- set reset high
Then the card has to start sending the Answer To Reset (ATR) whithin max. 40000 clock cycles.
For further information take a look at the specifications
Here you can find about what ISO/IEC 7816-3 says.
Here you can download the ETSI standards for free.
The one relavant for you is
ETSI TS 102 221
"Smart Cards; UICC-Terminal interface; Physical and logical characteristics"
With the details provided, it does seem like the crystal may be damaged - it's the most sensitive component on the board, and there's a good chance the pulser has been dropped a few times during it's long life.
The circuit seems reasonable and if it was originally designed with the resistor (rather than the capacitor), then I'd leave it like that. There are similar circuits out there that do use a capacitor as you say:
I'd go for replacing the crystal - choose a crystal designed for series operation such as the FOXLF160 (as opposed to the FOXLF160-20) While you're grabbing the crystal, getting a couple of 74LS38s wouldn't be a bad idea either, given they are only around 50 pence/cents each.
Also, given the price of decent CMOS oscillators nowadays, the other option is just to buy a 16MHz CMOS oscillator (5V supply tolerant) and replace the first stage with that.
Best Answer
The Pierce oscillator requires two capacitors! See this circuit.
The capacitor values depend on the crystal load capacitance; they are effectively in series so you need roughly twice the value of the load capacitance. You need to allow for stray capacitance.