MagTek TRIPLE TRACK Delta ASIC - Manual (Page 11)

Triple Track ASIC
7
SHIFT-OUT TIMING
The timing is shown in Figure 1. The timing diagrams are not to scale.
TIMING – TYPICAL APPLICATION WITH ISO DATA AND STROBE INDUCED RESET
CARD DATA 13 ZEROES AUX DATA DON'T CARE
Z FLAG FLAG CLR ?? VALID ?? VALID VALID ?? VALID RESETTING CLEAR
CLR FLAG STOP STRB 3 STRB 4 STRB 14,610
Tsc
Tdh
Tsd Tdh Tsd Tdh Tsd Tss Tsfc Tzf
TstbL_min
TstbH_min
TstbL_min
TstbH_min
TstbH_min TstbH_min
TstbL_min
TstbH_min
TstbL_min
TstbH_min
TstbL_min
TstbH_min
TstbL_min
TstbH_min TstbL_min TstbL_min
Head Signals
DATA
STROBE
TIMING – CUSTOM DATA APPLICATION; ALSO SHOWING PREMATURE RESET WITH
WATCHDOG
CARD DATA 13 ZEROES AUX DATA DON'T CARE
Z FLAG FLAG CLR ?? VALID ?? VALID ?? RESETTING CLEAR
CLR FLAG (STOP) STRB 3 STRB 4
Tsc
Twd
Tdh Tsd Tdh Tsd Taux Tsfc Tzf
TstbH_min TstbH_min TstbL_min
TstbH_min
TstbL_min
TstbH_min
TstbL_min
TstbH_min
TstbL_min
TstbH_min TstbL_min TstbL_min
Head Signals
DATA
STROBE
Figure 1. Timing
Tzf (Zeroes Flag) = 1/2 of a bit-cell maximum (25
μs to 3.3 ms maximum depending on card data rate)
Time from the last flux reversal of 13 consecutive zero-bits of the last track awake to the subsequent
falling edge of DATA. All active tracks must have completed 13 consecutive zero-bits for this flag to be
asserted. In a typical ISO card application, these 13 consecutive zero-bits are in the trailing-zero or
leading-zero (for a backwards swipe) area of the card, and this edge indicates to the controller that the
ASIC has ISO data in its buffer ready for extraction. Two STROBE pulses should be issued immediately
upon receiving this indication in most applications.
Tsfc (STROBE to FLAG CLEAR) = 2.4 μs maximum
Time from the falling edge of a STROBE pulse issued to clear the Zeroes Flag, until said flag is cleared.
Not a concern for typical ISO data applications. Used only with custom data formats that allow 13
consecutive zeroes as a valid sequence in the actual data portion of the card. Note that if the Auxiliary
Flag occurs before Tsfc expires, then DATA will not go high to indicate the Zeroes Flag has cleared.
Tss (STROBE to STOP) = 10
μs maximum
Time from the falling edge of a STROBE pulse issued to stop data collection until said data collection is
stopped and the DATA line assumes the BUFFER-READY state. The STOP-STROBE should be used
in typical ISO data applications to ensure that data is extracted as quickly as possible and to reduce
extraneous data collected in the ASIC’s buffer.