BioMax2 / KBio2-Online
Installation and Programming Manual
Page
84 of 91
A.3.2. Firmware Configuration
The Wiegand input is, effectively, the TTL_1 input with some tricky adjustments. For
that reason, once
is configured as stated below, the incoming data will be
treated by
BioMax2
just as if it were TTL_1. Implications will be seen further ahead.
Port activation
As said, Wiegand Input will be enabled through
CFG_Wiegand
, as
explained in
Following the case depicted in
, let
CFG_Wiegand
take value
$21
(i.e, 26-bit
Wiegand through TTL_1 port).
Configuration of the Main Reader
CFG_Reader_Enable
, to issue a
reception of a Wiegand frame. In a simple implementation, value
$08
on that parameter
will enable Wiegand reception through TTL_1.
A.3.3. Wiegand format explanation
Wiegand-26 bits format
The Wiegand-26 bit format allows a user-ID which contains 6 ASCII-Hex characters.
That is to say, user-ID codes numbered between
“0000000001”
and
“0000FFFFFE”
will be admitted.
Data format is as follows:
• Bit 0: first parity bit, “even” type. Its value is such, that the 13 first bits together
(bit 0 included) contain an even number of ones (
‘1’
).
• Bits 1 to 24: data corresponding to the 6 least significant characters of the user-ID,
transformed to binary.
• Bit 25: last parity bit, “odd” type. Its value is such, that the 13 last bits together (bit
25 included) contain an odd number of ones (
‘1’
).
Wiegand-34 bits format
There is no standard format for 34 bits, however we are keeping the same criteria as
above, for an 8 ASCII-Hex character user-ID. Therefore, user-ID codes in the range
between
“0000000001”
and
“00FFFFFFFE”
will be admitted.
Data format is as follows:
• Bit 0: first parity bit, “even” type. Its value is such, that the 17 first bits together
(bit 0 included) contain an even number of ones (
‘1’
).
• Bits 1 to 32: data corresponding to the 8 least significant characters of the user-ID,
transformed to binary.
