Binary to Ascii and Ascii to Binary converter in C

//This program is by Usmar A Padow (amigojapan) usmpadow@gmail.com
//converts ascii to binary and binary to ascii in C
//source https://www.youtube.com/watch?v=XykJzVbrf3s
#define MASK0 0x01
#define MASK1 0x02
#define MASK2 0x04
#define MASK3 0x08
#define MASK4 0x10
#define MASK5 0x20
#define MASK6 0x40
#define MASK7 0x80

unsigned char AtoB(char *ASCII) {//returns a unsigned char that is the binary value of the ascii sent
    //GeDaMo: amigojapan: well, those masks are a bit pointless, MASK0 is 1 << 0, MASK1 is 1 << 1 etc.
    //GeDaMo: amigojapan: also, |= exists so you can write a |= b instead of a = a | b
    unsigned char result;//this will contain the binary result
    if(ASCII[7]=='1') result = result | MASK0;
    if(ASCII[6]=='1') result = result | MASK1;
    if(ASCII[5]=='1') result = result | MASK2;
    if(ASCII[4]=='1') result = result | MASK3;
    if(ASCII[3]=='1') result = result | MASK4;
    if(ASCII[2]=='1') result = result | MASK5;
    if(ASCII[1]=='1') result = result | MASK6;
    if(ASCII[0]=='1') result = result | MASK7;
    return result;
}
#include<string.h>
#include<stdio.h>

unsigned char AtoB2(char *ASCII) {//returns a unsigned char that is the binary value of the ascii sent
    //GeDaMo: amigojapan: well, those masks are a bit pointless, MASK0 is 1 << 0, MASK1 is 1 << 1 etc.
    //GeDaMo: amigojapan: also, |= exists so you can write a |= b instead of a = a | b
    unsigned char result;//this will contain the binary result
    result=0;
    //printf("strlen(ASCII):%lu, ",strlen(ASCII));
    //if(strlen(ASCII)>sizeof(result)) return result;//exit gracefully if the ASCII is too long for the architecture we are on
    int up, down;
    for(up=strlen(ASCII)-1,down=0;down < strlen(ASCII);up--,down++) {
        int mask;
        mask=1 << down;
        if(ASCII[up]=='1') result |= mask;
    }
    return result;
}

//binary conversion function Binary to Ascii by GeDaMo
void BtoA(unsigned char ch, char *b) {
    int mask = 0x80;
    int i;

    for (i = 0; i < 8; ++i) {
        b[i] = ch & mask ? '1' : '0';
        mask >>= 1;
    }

    b[i] = '\0';
}

int main(void) {//test program to test both functions
    //char ASCII[9]="10101010";
    char ASCII[9]="1001";
    char ASCII2[9];
    unsigned char BINARY;
    BINARY = AtoB2(ASCII);
    BtoA(BINARY,ASCII2);
    printf("%s",ASCII2);
    return 0;
}