I have uploaded the rules, please explain step by step and which rule you have applied

Using the CCS Compiler method to solve this question Write a PIC16F877A program that flash ON the 8-LED's connected to port-B by using two switches connected to port-D (Do & D₁) as shown in figure below, according to the following scenarios: (Hint: Use 500ms delay for each case with 4MHz frequency) 1. When Do=1 then B₁,B3,B7 are ON. 2. When Do 0 then Bo,B2, B4, B5, B6 are ON. 3. When D₁=1 then B4,B,,B6,B7 are ON. 4. When D₁-0 then Bo,B1,B2,B3 are ON.

Use the ramp generator circuit in Fig. B2a to generate the waveform shown in Fig. B2b. Write four equations relating resistors R1, R2, R3, capacitor C and voltages Vs, VR and VA.to the waveform parameters T₁, T, Vcm and Vm- If R = R2 = R3, R₁ = 2R, C = 1 nF, Vcm = 2 V and Vm = 1 V, T₁ = 2 μs and T = 10 μs solve for the values of R, Vs, VR and VA using your equations from part a(i). VR C +VA R3 V₂ Vo мат R1 VsO+ V₁ R₂ Figure B2a Vout Vcm+Vm Vcm Vcm-Vm 0 T₁ T 2T time Figure B2b