Remote-processing CAMBASIC Instrukcja Użytkownika Pobierz pdf (Strona 42)

Commands - 9

BIN

Numeric Fun ction

SYNTAX: n = BIN(m)

PURPOSE: To return a number from a packed BCD number.

REMARK S: This function assumes that the BCD digits are packed. That is, there are four BCD digits per

16– bits.

EXAMPLE: A = BIN(B)

Normally, the only way BCD data can enter the system is through an I/O port like those on the

82C55 (e.g. reading a two digit BCD thum b wheel switch).

Each of the two switches has four outputs. Together, the eight lines are connected to an I/O port

input. Assuming the thumb wheel switches are set to 98 and connected to I/O port &18, the port

input would look as follows (where D0 through D7 are the eight data bits):

D7 D6 D5 D4 D3 D2 D1 D0

1 0 0 1 1 0 0 0

The example below appears wrong at first. However, CAMBASIC assumed that this was a binary

number and gave you the de cimal equivalent.

PRINT INP(&18)

152

To get the corre ct result:

PRINT BIN(INP(&18))

ERROR: < Illegal argument> – if any BCD digit > 9

< Data negative > – for m

1 2 ... 37 38 39 40 41 42 43 44 45 46 47 ... 207 208

Brak uwag

Remote-processing CAMBASIC Instrukcja Użytkownika Strona 42