Remote Processing CAMBASIC - Manual (Page 42)

Comm ands - 9
BIN
Numeric Fun ction
SYNTAX: n = B IN (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)
Norm ally, 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):
D 7 D 6 D 5 D 4 D 3 D 2 D 1 D 0
1 0 0 1 1 0 0 0
The example below appears wrong at first. However, CAMBASIC assumed that this was a binary
numbe r and ga ve you the de cimal equ ivalent.
PRINT INP(&18)
152
To get the c orre ct result:
PRINT BIN(INP(&18))
98
ERROR: < Illegal arg ument> – if any BCD digit > 9
< Data negative > – for m