TMS320F280049C: Can PGA_IN IO be used as general ADC input？ TMS320F280049C Crystal design consideration

Hi '0721,

(1)

This will depend on what size package you have.  Smaller pincount packages have the PGA input double-bonded with a bare ADC input.  You can see the specific connections in the datasheet or TRM in the "Analog Pins and Internal Connections" table.  For instance, on the 100-pin pacakges, PGA1_IN is only ever a PGA input (on pin 18), but on the 64-pin package, PAG1_IN shares a pin with ADC input C0. 

This situation is also shown in the analog group connections diagram.   

(2) I'm not sure what general information we have other than what is in the datasheet section "Crystal Oscillator".  We also have a HW design guide with similar information to the DS here: https://www.ti.com.cn/cn/lit/an/spracz9/spracz9.pdf and this e2e thread: https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/965458/tms320f280049-cyrstal-circuit-design-questions/3567573 

Otherwise, you are definitely going to want to place the XTAL and associated components as close to the X1 and X2 pins as practical in your layout  (I think preferably on the same side of the PCB as the C2000 device) and try to keep any sensitive components further away from the XTAL.