unsigned char code seg_table[] = {0xc0, 0xf9, 0xa4, 0xb0, 0x99, 0x92, 0x82, 0xf8, 0x80, 0x90}

This is an array of hexadecimal values representing the segment patterns for displaying numbers on a 7-segment display. Each value corresponds to a specific digit from 0 to 9. The values are in hexadecimal format, which means they range from 0x00 to 0xFF. In this case, the values are all between 0x80 and 0xF9.

The 7-segment display is a common type of electronic display that can be used to display numbers and some letters. The display is made up of seven segments that can be turned on or off to create different patterns that represent different numbers or letters. Each segment is assigned a letter (a to g) and a decimal point (dp) to indicate which segments should be turned on to display a specific character.

The values in the array correspond to the segments that should be turned on to display each digit. For example, the first value (0xC0) represents the segment pattern for the number 0. The first bit (bit 0) is the segment a, the second bit (bit 1) is the segment b, and so on, up to the seventh bit (bit 6), which is the decimal point. The values in the array were likely determined experimentally or through reference to a datasheet for the specific type of 7-segment display being used.