Echelon FT 3150 Smart Transceiver - Manual (Page 66)

Chapter 3 - Input/Output Interfaces
60 FT 3120 / FT 3150 Smart Transceiver Data Book
Figure 3.25 I
2
C I/O Object
Magcard Input
This I/O object is used to transfer synchronous serial data from an ISO 7811 Track 2 magnetic stripe card reader in
real time. The data is presented as a data signal input on pin IO9, and a clock, or a data strobe, signal input on pin IO8.
The data on pin IO9 is clocked on or just following the falling (negative) edge of the clock signal on IO8, with the
Parameter Description Min Typ Max
t
f
I/O call to start condition
io_in()
io_out()
—
— 54.6 µs
43.4 µs —
—
t
start
End of start condition
io_in()
io_out()
5.4 µs
5.4 µs —
— —
—
t
cla
End of start to start of address
io_in()
io_out()
24.0 µs
24.0 µs —
— —
—
t
cld
SCL low to data for io_out() 24.6 µs — —
t
dch
Data to SCL high for io_out() 7.2 µs — —
t
chcl
Clock high to clock low for io_out() 12.6 µs — —
t
chd
SCL high to data sampling for io_in() 13.2 µs — —
t
dcl
Data sample to SCL low for io_in() 7.2 µs — —
t
clch
Clock low to clock high for io_in() 24.0 µs — —
t
stop
Clock high to data
io_in()
io_out()
12.6 µs
12.6 µs —
— —
—
t
ret
SDA high to return from function
io_in()
io_out()
—
— —
— 4.2 µs
4.2 µs
IO10
IO9
IO8
IO0
IO1
IO2
IO3
IO4
IO5
IO6
IO7
t
dch
SCL
SDA
TIME
START OF
io_in() OR
io_out()
INPUT DATA
SAMPLED
t
chcl
t
cld
t
chd
t
dcl
t
clch
SCL
SDA
TIME
t
stop
t
ret
t
f
t
start
t
cla
END OF
io_in() OR
io_out()
BIT TRANSFER TIMING START AND STOP TIMING
Clock
Serial Data