MPPT solar panel controller

PIC16F1782 has got built in almost all components needed to build a switching regulator. I've already tested a possibility of building step down regulator utilizing a microcontroller with "advanced analog peripherals". This time I would like to build a true maximum power point tracking converter for a solar panel. 

My monocrystalline test solar panel is rated with:

Peak Power (Pm) 10W

Open Circuit Voltage (Voc) 21.67V

Short Circuit Current (Isc) 0.61A

Maximum Power Voltage (Vmp) 17.49V

Maximum Power Current (Imp) 0.57A

Maximum power voltage is lower than voltage needed to charge a 12V lead battery so I need a step-down converter:

I found it difficult to arrange which pins should be connected to which signals. There are some alternatives on which pins periferals are connected and it is rather difficult to notice the best arrangement looking only at schematic. It is much easier to notice every possibilities and clashes on a spreadshit like this:

	pin								1st	2nd
RA0	2	AN0	CxIN0-						COMP_I
RA1	3	AN1	CxIN1-	OPA1OUT					PV_I_SHUNT
RA2	4	AN2	CxIN0+						COMP_I
RA3	5	AN3	C1IN+						PV_I_FBK
RA4	6		C1OUT	OPA1IN+					PV_I_SHUNT
RA5	7	AN4	C2OUT	OPA1IN-					PV_I_SHUNT
RA6	10		C2OUT						COMP_I
RA7	9				PSMCxCLK
RB0	21	AN12	C2IN1+		PSMCxIN	CCP1(2)			STOP_SWITCHING
RB1	22	AN10	CxIN3-	OPA2OUT					COMP_V
RB2	23	AN8		OPA2IN-					PV_U_FBK
RB3	24	AN9	CxIN2-	OPA2IN+		CCP2(2)			OUT_V_FBK
RB4	25	AN11	C3IN+						COMP_V
RB5	26	AN13	C3OUT						COMP_V
RB6	27						TX(2)	ICSPCLK	PROG	TX
RB7	28						RX(2)	ICSPDAT	PROG	RX
RC0	11				PSMC1A
RC1	12				PSMC1B	CCP2(1)			PV_I_SET_PWM
RC2	13				PSMC1C	CCP1(1)			PV_V_SET_PWM
RC3	14				PSMC1D
RC4	15				PSMC1E				LED2
RC5	16				PSMC1F				LED1
RC6	17				PSMC2A		TX(1)		DRIVE_HS
RC7	18				PSMC2B		RX(1)		DRIVE_LS
RE3	1								PROG
VDD	20
VSS	8
VSS	19