Q: What is the difference between the 4MHz and 8MHz crystal on EasyPIC2 development board?
A: If you have some time-critical stuff that require greater speed that the 4MHz crystal can give, you should certainly go for 8MHz. Otherwise, it is (should be ) quite the same. The basic reason we introduced 8MHz on EasyPIC2 is to reduce the number of parts used in production. BTW, it works fine with 20MHz as well.
You must take care about the clock frequency for which each example is compiled. Nowadays we deliver all the examples compiled to 8MHz, but you might still find some of them done for the 'good old' 4 MHz clock. Also, in some cases when compiler (mikroBasic /mikroPascal) crashes, it resets the device frequency back to 4MHz.
<Beginner> Difference between the 4MHz and 8MHz crysta
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- Posts: 122
- Joined: 28 Apr 2009 16:16
Re: <Beginner> Difference between the 4MHz and 8MHz crysta
20 MHZ enters the pic mcu and is devided by 4, this means time for executing one cycle = 1/[20/4] = 200 nano second,
for 4 MHZ = 1/[4/4] = 1 micro second
for 4 MHZ = 1/[4/4] = 1 micro second
Re: <Beginner> Difference between the 4MHz and 8MHz crysta
But used crystal affects the UART baud rates, right? I mean, the error rate of them...
- lana.arsic
- mikroElektronika team
- Posts: 1715
- Joined: 15 Jan 2016 12:50
Re: <Beginner> Difference between the 4MHz and 8MHz crysta
Hi,
Higher baud rate increases possibility of an error occurring.
Used crystals affects only on the maximum baud rate.
Best regards,
Lana
Higher baud rate increases possibility of an error occurring.
Used crystals affects only on the maximum baud rate.
Best regards,
Lana
Re: <Beginner> Difference between the 4MHz and 8MHz crysta
For high baud rates you can substitute a "exact" crystal, 7.3728MHz is available and allows for most baud rates with integer division ratios.