Apalis Carrier Board Design Guide - Toradex

Apalis Carrier Board Design GuideThe Mini PCIe Card features the decoupling capacitors for the RX lines on the card. Therefore, noadditional decoupling capacitors should to be placed on the carrier board in either the RX, TX orreference clock lines.USBHostUSBHn_D+USBHn_D+USB_D+USBHn_D-USBHn_D-USB_D-USBDeviceTXPCIeHostPCIE1_TX+PCIE1_TX-2x 100nFModuleConnectorPCIE1_TX+PCIE1_TX-PET0+PET0-PCIe Mini CardConnectorRXPCIeDevicePCIE1_RX+PCIE1_RX+PER0+RXPCIE1_RX-PCIE1_RX-PER0-TX2x 100nFApalis Module Carrier Board PCIe Mini CardFigure 8: Mini PCIe Card Block DiagramThe Apalis module standard does not feature a dedicated PCIe reset output as it does not providethe PCIe hot-plug functionality. Therefore, the PCIe reset input (PERST#, pin 22) of the card shouldbe served by the general module reset output (RESET_MOCI#). Some Apalis modules mightprovide the additional hot-plug signals such as reset and hot-plug detect as secondary functions oras type-specific interfaces. Nevertheless, as compatibility between different Apalis modules couldnot be guaranteed by using these hot-plug signals, it is recommended that the RESET_MOCI#signal is used as reset.The clock request output of the card (CLKREQ#, Pin 7) can be left unconnected. It might also beconnected to a free GPIO on the Apalis module. In this case, the clock request functionality needsto be implemented in software.The wake output of the Mini PCIe Card (WAKE#, pin 1) can be connected to the general wakeinput of the Apalis module (WAKE1_MICO#). Wake-up-capable Mini PCIe Cards such as Wi-Ficards can use this signal to wake up the module from its suspend state.The R-UIM interface of the Mini PCIe Card (UIM, pin 8, 10, 12, 14 and 16) are only needed formobile broadband modem cards such as 3G cards. If the card interface needs to support suchmodems, an additional SIM card holder needs to be attached to this interface.The Mini PCIe Card pin-out features an SMB interface for additional power management control.As the SMB and I2C buses are compatible, it is recommended that the I2C1 interface on the Apalismodule is used if the SMB interface is needed. Most PCIe cards do not make use of the SMBinterface. Therefore, these pins can be left unconnected for most applications.Toradex AG l Altsagenstrasse 5 l 6048 Horw l Switzerland l +41 41 500 48 00 l www.toradex.com l info@toradex.com Page | 16