Kontron COMe Starterkit Eval T2 - Manual (Page 130)

COM Express Interfaces
2.22.1. Module Type Detection
The COM Express Specification includes three signals to determine the pin-out type of the
Module connected to the Carrier Board. If an incompatible Module pin-out type is detected,
external logic should prevent the Carrier Board from powering up the whole system by controlling
the 12V supply voltage. The pins 'TYPE0#', 'TYPE1#' and 'TYPE2#' are either left open (NC) or
strapped to ground (GND) by the Module to encode the pin-out type according to the following
table. The Module Type 1 has no encoding. For more information about this subject, refer to the
COM Express Specification.
Table 43: Module Type Detection
Module Type Pin TYPE0# Pin TYPE1# Pin TYPE2# Pin TYPE10#
Module Type 1 X (don't care) X (don't care) X (don't care) 12V or NC
Module Type 2 NC NC NC 12V or NC
Module Type 3 NC NC GND 12V or NC No IDE interface
Module Type 4 NC GND NC 12V or NC No PCI interface
Module Type 5 NC GND GND 12V or NC No IDE, no PCI interface
Module Type 6 GND NC NC 12V or NC No IDE, no PCI interface
Module Type 10 X (don't care) X (don't care) X (don't care) PD with 47k
Pin TYPE10# is reclaimed from the VCC_12V pool. In R1.0 Modules this pin will connect to
other VCC_12V pins. In R2.0 this pin is defined as a no connect for types 1-6. A Carrier can
detect a R1.0 Module by the presence of 12V on this pin. R2.0 Module types 1-6 will no connect
this pin. Type 10 Modules shall pull this pin to ground through a 47K resistor.
Figure 51 below illustrates a detection circuitry for Type 2 Modules. If any Module type other than
Type 2 is connected, the 'PS_ON#' signal, which controls the ATX power supply, is not driven low
by the Module, and hence the main power rails of the ATX supply do not come up. The Type
Detection pins of the Module must be pulled up on the Carrier Board to the 5V Suspend voltage
rail.
PICMG ® COM Express ® Carrier Board Design Guide Rev. 2.0 / December 6, 2013
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