Datasheet

217
32142D–06/2013
ATUC64/128/256L3/4U
13.6.6 Reset Controller
The Reset Controller collects the various reset sources in the system and generates hard and
soft resets for the digital logic.
The device contains a Power-on Reset (POR) detector, which keeps the system reset until
power is stable. This eliminates the need for external reset circuitry to guarantee stable opera-
tion when powering up the device.
It is also possible to reset the device by pulling the RESET_N pin low. This pin has an internal
pull-up, and does not need to be driven externally during normal operation. Table 13-6 on page
217 lists these and other reset sources supported by the Reset Controller.
Figure 13-3. Reset Controller Block Diagram
In addition to the listed reset types, the JTAG & aWire can keep parts of the device statically
reset. See JTAG and aWire documentation for details.
Table 13-6. Reset Description
Reset Source Description
Power-on Reset
Supply voltage below the Power-on Reset detector threshold
voltage V
POT
External Reset RESET_N pin asserted
Brown-out Reset
VDDCORE supply voltage below the Brown-out detector
threshold voltage
JTAG
Reset
Controller
RESET_N
Power-on Reset
Detector(s)
OCD
Watchdog Reset
RCAUSE
CPU, HSB, PBx
OCD, AST, WDT,
Clock Generator
Brown-out
Detector
AWIRE
SM33 Detector