1-Write assembler directives to define the ASCII codes of letters a to z in program memory. 2- Write assembler directives to define the ASCII codes of digits 0 to 9 in program memory starting from address 0x1000. 4- Write a program to add the 16-bit numbers stored at data memory locations 0x210-0x211 and 0x220-0x221, respectively, and store the sum at 0x230-0x231