Programmer Controlled Target Discharge Circuit - Equinox Systems ISPnano I Series User Manual

Distributor of Equinox Technologies: Excellent Integrated System Limited
Datasheet of ISPNANO S3 KIT - ISP PORTABLE PROGRAMMER
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4.7 Programmer controlled Target Discharge Circuit

The ISPnano programmer features a programmer controlled 'Target Discharge Circuit' which can
be used to automatically discharge any residual charge stored on the Target System (UUT) after the
target power has been switched off. This feature can be fundamental in preventing ESD damage to
both the UUT and programmer if a UUT is removed from a Programming Fixture while it still has
residual charge on it.
As soon as the target power supply has been switched off, the programmer automatically switches a
resistive load across the Target System (UUT) which discharges any energy stored in reservoir
capacitors on the UUT. The programmer constantly monitors the 'Target Voltage' on the TVCC pin
until the voltage has decayed to a specified voltage e.g. <200 mV at which point the programmer
signals that the UUT is safe to remove from the programming fixture. If the 'Target Voltage' does not
decay to the specified voltage in the user-programmable 'discharge timeout' period, then an error
condition is generated.
Features:
Programmer controlled 'Target Discharge Circuit'
•
Switches a 'resistive load' (120 ohm resistor) across the 'Target Load' (TVCC and
•
GROUND) to discharge the UUT
Used to automatically discharge any energy stored in reservoir capacitors on the Target
•
System (UUT) after the UUT power has been switched off
Prevents ESD damage to the UUT by ensuring there is no energy left in the UUT when it is
•
disconnected from the programmer
64 ISPnano Series Programmer - User Manual – V1.11 – 12
th
May 2011