User guide

Chapter 3 - Input/Output Interfaces
62 FT 3120 / FT 3150 Smart Transceiver Data Book
Magtrack1 Input
This input object type is used to read synchronous serial data from an ISO3554 magnetic stripe card reader. The data
input is on pin IO9, and the clock, or data strobe, is presented as input on pin IO8. The data on pin IO9 is clocked in
just following the falling edge of the clock signal on IO7, with the LSB first.
Figure 3.27 Magtrack1 Input Object
The minimum period for the entire bit cycle (t
clk
) is greater than the sum of t
low
and t
high
. The t
setup
and t
hold
times should be such that the data is stable for the duration of t
low
.
Symbol Description Min Typ Max
t
fin
Function call to first clock input — 45.0 µs —
t
hold
Data hold t
low
— t
clk
t
setup
Data setup 0 µs — —
t
low
Clock low width 31 µs — —
t
high
Clock high width 31 µs — —
t
wto
Width of timeout pulse 60 µs — —
t
clk
Clock period 138 µs — —
t
tret
Return from timeout 21.6 µs — 81.6 µs
t
ret
Return from function — — 301.8 µs
Serial Data
Clock
IO10
IO9
IO8
IO0
IO1
IO2
IO3
IO4
IO5
IO6
IO7
Timeout
t
wto
CLOCK
(IO8)
SDA
(IO9)
TIMEOUT
START OF
io_in()
t
hold
END OF
io_in()
t
setup
t
high
t
ret
t
fin
TIME
t
low
t
tret
t
clk