Dataman S4 - Manual (Page 46)

DATAMAN S4 MANUAL
46 EMULATE KEY
write-line must not be connected through the
EMULead, but must go directly to the Flying
Write Lead. One way to do this might be to cut
the Write-pin off a spare EMULead, used only
for this purpose. Another way is to use an
intermediate socket plugged into the EMULead,
which has the write-pin removed.
Power Usage when Emulating.
The time-out termination is disabled while
emulating, but the low-battery termination still
works. Emulation places an extra current-drain
on the battery: the actual current depending on
the load driven by the data-pins and the
amount of time the internal memory is enabled.
100 milliamps is typical which is about 6hrs on
a full charge. If the charger is plugged-in then
there is no time-limit. The ESCape key will
terminate the emulate mode.
Line Terminations of the EMULead
All the DATA, ADDRESS and CONTROL lines
are connected to logic inputs or outputs of
74HCT series gates via series 150Ω resistors
within S4: this minimizes over- and under-
shoot without compromising output drive too
much. To prevent the lines floating when
disconnected, which would cause unnecessary
power dissipation, all lines have 100KΩ
resistors pulling then to the 5 volt or ground
rails. To minimize current-drain when
emulating, it is preferable that inputs should be
driven right to the 5v and 0v rails. Drive current
taken from the data-outputs should be kept to
a minimum.