Difference between revisions of "Reset scheme (Bora/BoraLite)"

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== Reset scheme and voltage monitoring ==
 
== Reset scheme and voltage monitoring ==
 
The following picture shows the simplified block diagram of reset scheme and voltage monitoring.
 
The following picture shows the simplified block diagram of reset scheme and voltage monitoring.

Revision as of 15:32, 24 March 2014

Info Box
Bora5-small.jpg Applies to Bora

Reset scheme and voltage monitoring[edit | edit source]

The following picture shows the simplified block diagram of reset scheme and voltage monitoring.

Bora-reset-scheme.png

Two reset signals are available. They are described in detail in the following sections.

PORSTn[edit | edit source]

This is a bidirectonal open-drain signal that is connected to Zynq's PS_SRST_B and can be asserted by the following devices:

  • a multi-rail voltage monitor that monitors 3.3VIN power rails and all of the rails generated by Bora's PSU. This monitor
    • in case of a power glitch, asserts MEM_WPn signal in order to prevent any spurious write operation on flash memories too. MEM_WPn is 3.3V, push-pull, active low.
    • has a timeout of about 1ms.
    • provides MRSTn debounced input for manual reset (for example to connect a push-button). This signal is pulled-up to 3.3VIN through a 2.2kOhm resistor.
  • a watchdog timer (Maxim MAX6373). For more details please refer to Watchdog section.

PORSTn is pulled-up to 3.3VIN through a 2.2kOhm resistor.

SYS_RSTn[edit | edit source]

This signal is connected to Zynq's PS_SRST_B and is pulled-up to 1.8V through a 20kOhm resistor.