using SMD adapter for PIC microcontrollers
Est wrote 06/05/2017 at 07:35 • 0 pointsI am doing a project using a PIC24EP32GP202 in a DIP package.
I found myself short of pins and I am thinking to use a bigger brother in a SMD package. Using this PIC in DIP package i found out that is very sensible to the layout, for example it does not work on a bread board because the connections to decoupling capacitors are too long, it keeps resetting, if it mounted in a socket with all the connections soldered on a prototyping board it works fine.
This PIC runs at 140 Mhz using a PLL and a quartz of 8Mhz (in my case)
I would like to try the SMD version with more pins and use an adapter to develop the project but I worry about the following points:
Will the length of the connections to the decoupling capacitors be too long and have the same problems i found using the bread board?
As the length between the PIC pins and the quartz will be too long, can I use an external oscillator and supply the signal at logic level to the PIC to overcome the distance problem? In this case I will use a 12 Mhz oscillator and obtain 140 Mhz using the internal PLL.
Any suggestion is very appreciated.
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thank you so much!
Yes the Pic allows to select an external source for the clock.
I will try to solder the caps as you said
Are you sure? yes | no
Usually PICs allow you to configure the oscillator input to use an external clock signal. But if this doesn't allow it, you can use something like this:
This reduces the voltage level enough to be used for a crystal input without damaging it or causing too much distortions. I tested this successfully with a LPC11U2X microcontroller.
Regarding the decoupling capacitors: You can easily solder some SMD caps near the pins of the microcontroller on the adapter, or leaded capacitors directly glued on top of the microcontroller, if the pins are too far apart.
Are you sure? yes | no