4 exiting the loader, Xiting the, Oader – Maxim Integrated Secure Microcontroller User Manual
Page 139
Secure Microcontroller User’s Guide
139 of 187
16.4 Exiting the Loader
In the DS5000 series, the RST pin must be driven low or allowed to float and the
PSEN
signal should be
allowed to float. The RST pin has an internal pulldown. The
PSEN
is an output and drives itself. Note
that both of these conditions must occur or the loader will not be exited. For the DS5001/2, there are
several options. If the RST and
PSEN
option is used, they must be removed as described above. If
PROG
is pulled low, it can either be returned high or the Exit “E” command can be issued. Since the loader is
edge activated, this will restart the user’s code even while the
PROG
pin is low. If power were to cycle
while the
PROG
pin were low, the loader would be invoked on power-up. The flow of these conditions is
shown in