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9.7. LPC
The Low Pin Count (LPC) Interface signals are connected to the LPC Bus bridge located in the Soc. The LPC low speed
interface can be used for peripheral circuits such as an external Super I/O Controller that typically combines legacy-
device support into a single IC. The implementation of this subsystem complies with the COM Express® specification.
The COM Express® Design Guide maintained by PICMG provides implementation information or refer to the official
PICMG documentation for more information.
The LPC bus does not support DMA (Direct Memory Access). When more than one device is used on LPC, a zero delay
clock buffer is required. This leads to limitations for ISA bus and SIO (standard I/O(s) like floppy or LPT interfaces)
implementation. The COMe-bDV7 LPC clock buffer allows for the connection of three LPC devices
All Kontron COM Express® Computer-on-Modules include BIOS support for the following external carrier board LPC
Super I/O controller features for the HWM chip Nuvoton NCT7802Y.
Table 16: Supported BIOS Features
HWM Feature
COM1/COM2, FPGA, TPM
PS/2, LPT, HWM, Floppy, GPIO
Features marked as not supported do not exclude OS support, except for, HWM that is controlled within the BIOS
Advanced setup menu and has no OS software support. The HWM is accessible via the System Management (SM) Bus.
For more information, see Chapter 10.6: System Management (SMBus)
If any other LPC Super I/O additional BIOS implementations are necessary, contact Kontron Support.
9.8. Radid Shutdown
Kontron has implemented a rapid shutdown function on R E2 modules variants. Rapid shutdown performs a
controlled accelerated system shutdown and functions as follows:
1.
An active-high shutdown signal is asserted by the COM Express Eval Type 7 carrier board through pin C67 of the
COM Express connector. The characteristics of the shutdown signal are as follows:
Amplitude 5.0 V +/- 5%
Rise time ⇐ 1 µs
Source impedance < = 50 ohms
Duration >= 20 µs
The assertion of this signal causes all power regulators to be disabled and the internal power supply rails to be
discharged by crowbar circuits. The shutdown circuitry provides internal energy storage that maintains crowbar
activation for at least 2 ms following the de-assertion of the shutdown signal. The circuit also incorporates a
weak input pull-down resistor so that the module operates normally in systems where the rapid shutdown
functionality is not used and pin C67 (RAPID_SHUTDOWN
2.
Simultaneously with the leading edge of shutdown, the 12 V (main) input power to the module is removed and
these input power pins are externally clamped to ground though a crowbar circuit located on the COM Express
carrier board. This external clamping circuit must maintain a maximum resistance of approximately 1 ohm and be
activated for a minimum of 2 ms.
3.
Simultaneously with the leading edge of shutdown, the 5 V (standby) input power to the module is removed, if
present. External clamping on these pins is not necessary (but recommended) because it is clamped through the
module by the main 12 V rail.
www.kontron.com
AMI EFI APTIO V
Supported
Not supported
of the COMe connector is left unconnected.
)
COMe-bDV7 - User Guide, Rev 1.0
// 41
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