Product specifications

CashFlow
®
9520 / 9524 / 9528 Design Guide
©
MEI., 2003 Page 28 Rev: G1
Output Common Specification
Sample multiplexed implementation - Negative Common Strobe
Cashflow
126
Outputs
A
B
C
D
E
F
OutputCom
Strobe 1
Strobe 2
A
B
C
D
E
F
A
B
C
D
E
F
Multiplexed
Bus
Vcc
Option
Switches
etc.
R ohms
I= 6xVcc/R
Rx10
(470)
(4k7)
(150mA)
Output common can be left floating for multiplexed implementations. However the minimum
turn on time when output common was floating is 15 micro seconds. If the polarity is
established on output common by means of a weak pull up (for -ve com) or pull down (-ve
com) the turn on time can be reduced. In the case above, the maximum time from the
output common being strobed to the output being true is approximately 1 micro second.
See the diagrams below for sample multiplexing implementation.
If output common is changed form negative to positive common (or vice versa) during
polling, the state of any coin output cannot be guaranteed for 15us.