Kontron COMe-cP2020 - Manual (Page 20)

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COMe-P2020 User Guide
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2.2.2.2 SPI OS/User Flash
The COMe-cP2020 supports 8 MB of soldered flash memory for the OS.
2.2.2.3 NAND Flash
The COMe-cP2020 supports up to 2 GB of soldered NAND flash memory, which is an SLC-based NAND flash. It is optimized for
embedded systems providing high performance, reliability and security.
2.2.2.4 MRAM Memory
The COMe-cP2020 supports 512 kB of MRAM memory (Magnetorestrictive Random Access Memory) for fast non-volatile
data storage (optional).
2.2.2.5 SDHC Socket
The COMe-cP2020 is provided with a microSDHC card socket, J1, which accepts microSD and microSDHC cards up to 32 GB. If
used, the card must be installed prior to installation of the COMe-cP2020 in a system.
If the SDHC interface is routed to the COM Express connector (via DIP switch SW1, switch [1]), the onboard socket J1 cannot
be used.
2.2.3 System/User Data EEPROMs
The COMe-cP2020 provides two 64-kBit EEPROMs, one for system data storage and one which is free for user data storage.
The user data EEPROM is accessible via the OS or an application. The system data EEPROM is reserved for system usage.
2.3 Timer
The COMe-cP2020 is equipped with the following timer:
• Real-Time Clock (RTC)
The COMe-cP2020 is equipped with an onboard high-precision real-time clock RV-8564-C3. The RV-8564-C3 RTC is register-
compatible with the PCF8564A RTC from Philips/NXP. In addition, it provides a very tight frequency tolerance at low power
consumption. The COMe-cP2020 does not include a 3 V lithium battery or a GoldCap power source for RTC backup. Power for
the RTC is supplied by the carrier via the VCC_RTC pin.
2.4 Watchdog Timer
The COMe-cP2020 provides a Watchdog timer that is programmable for a timeout period ranging from 125 ms to 4096 s in
16 steps. Failure to trigger the Watchdog timer in time results in a interrupt or a system reset or both. In dual-stage mode,
it results in a combination of both interrupt and reset if the Watchdog is not serviced. A hardware status flag will be pro-
vided to determine if the Watchdog timer generated the reset. Refer to the Watchdog Timer Control Register (WTIM) in
Chapter 3 for further information.
There are four possible modes of operation involving the Watchdog timer:
• Timer only mode
• Reset mode
• Interrupt mode
• Dual stage mode
At power on the Watchdog is not enabled. If required, the bits of the Watchdog Timer Control Register must be set according
to the application requirements. To operate the Watchdog, the mode and time period required must first be set and then
the Watchdog enabled. Once enabled, the Watchdog can only be disabled or the mode changed by powering down and then
up again. To prevent a Watchdog timeout, the Watchdog must be retriggered before timing out. This is done by writing a ‘1’
to the WTR bit. In the event a Watchdog timeout does occur, the WTE bit is set to ‘1’. What transpires after this depends on
the mode selected.