5. FUNCTIONAL OVERVIEW
This page describes the key sub-systems implemented on the Jetbox-Floyd system.
5.1 Power Supply Specifications
Gemini carrier board is powered by a wide range of power supply ranging from +12V to 28VDC(+/-10%). The maximum permissible reflected ripple measured at the voltage input connector is +/-100mV p-p.
All required supply voltages for the board are derived from the 12V-30VDC input. The maximum power required with the COMExpress module loaded and all interfaces along with addon-cards installed is 95W.
5.2 Backup Battery
A 2x1 right angle connector is available to support an external RTC battery connection. The Voltage level for RTC is 3V.
The Current requirement for RTC: 4uA.
Back-up time for CR2032: 56250 hours
5.3 Digital I/O
Gemini includes a CP2112 USB to GPIO expander to provide 8 GPIO lines which are accessible on a 2x5 2mm pitch pin header. All GPIOs are 3.3V compatible. CP2112 is a USB to SMBus bridge IC which has 8 GPIO lines. Gemini is making use of these GPIO lines for DIO capability. CP2112 is USB HID IC. No additional drivers are required.
USB to GPIO is shared with mPCIe socket. GPIO is selected as default. A jumper selects which device is active.
Refer to section 11 for jumper details.
5.4 Display Output Controller
Gemini has 3 video output ports available, one LVDS and 2 HDMI. Simultaneous video output on 3 video ports is supported.
5.4.1 LVDS LCD Connector
Gemini supports a 24-bit dual-channel LVDS display accessible on a 2x15 right-angle latching connector. The backlight supply and PWM control signals are provided on a separate right-angle connector. The backlight supply and LCD supply are user selectable using the JP2 jumper to support multiple LCD displays.
For enabling the LVDS display eDP/LVDS should be enabled and the LFP panel type resolution should be set as 1920x1080.
5.4.2 HDMI ports
Gemini SBC offers two HDMI 1.4 video output ports routed from the module. The HDMI ports are made available on two separate 2x10 2mm pitch pin headers. HDMI Integrated audio is supported on HDMI ports.
PTN3363BSMP low power HDMI/DVI level shifter is used to level shift AC coupled differential DDI signals to HDMI 1.4b compliant differential signals. PTN3363BSMP also takes care of HPD and DDC signal level translation.
5.5 Ethernet Ports
Two Gigabit Ethernet ports are available. Both ports support 10/100/1000 MBPS.
One Ethernet port is available directly from the COM module
The second port is implemented using the WI210 Ethernet controller via x1 PCIe lane from the module.
Both Ethernet ports are accessible on 2 2x5 2mm pitch header compatible with Diamond systems standard Ethernet cables.
There are 3 LEDs for each port indicating activity and speed.
5.6 Audio Interface
Audio codec ALC892-CG converts HD audio signals from module to analog audio signals which are accessible over a standard 2x5 pin header. The audio I/O signals include the below signals:
Stereo Line-In
Stereo Line-Out
Mic-In
5.7 LED Indicators
Gemini has 10 LEDs on board to indicate board and Ethernet status.
Function | LED Color and Operation | PCB Label |
Power Input | Supplied Power Input | PWR IN |
Power GOOD | Green LED indicates Power Supply is Good | PWR ON |
BOOT LED | Green LED indicates Module Booted Successfully | BOOT |
USER LED | Green LED indicates USER selectable status | USER |
Ethernet | Green LED indicates Activity and Speed Status of Each Port | ACT-P1, 100-P1,1G-P1 & ACT-P2, 100-P2, 1G-P2 |
5.8 PCIe Link routing
cExpress-WL 8665UE module supports 8 x1 lanes. PCIe lanes are routed from module to support Serial port, mPCIe socket, Ethernet port, PCIe to PCI bridge, and PCIe/104 expansion.
All Gemini variants have PCIe x16 lane connected to PCIe/104 banks 2 & 3.
The x16 PCIe lane support is module dependant
The lanes are routed from the COM module and mapped to the on-board I/O interfaces and expansion sockets as specified in the following table and the diagram below.
PCIe Lane from COM Module | Function |
Lane 0 | Gigabit Ethernet |
Lane 1 | PCIe/104 x1 Lane0 |
Lane 2 | quad UART |
Lane 3 | mini-card socket |
Lane 4 | PCIe/104 x1 Lane1 |
Lane 5 | PCI-104 |
Lane 6 | PCIe/104 x1 Lane2 |
Lane 7 | PCIe/104 x1 Lane3 |
5.9 PCIe mini-Card Socket
Gemini is equipped with a PCIe mini-card full-size socket to support full-size PCIe and USB2.0 mini-cards. USB to mPCIe socket is shared with GPIO. GPIO is selected as default. A jumper selects which device is active.
Two threaded spacers are provided on the Gemini carrier card for installing PCIe mini-card module
Refer to section 11 for jumper details.
5.10 M.2 Socket
Gemini has one SATA port from module routed to M.2 M-key socket to support M.2 SSDs. The M.2 Formfactor supported is 2242(22mm W x 42mm L). A threaded spacer is provided on the Gemini carrier card for installing M.2 module.
5.11 SATA connector
Gemini has one SATA port accessible on a standard 7-pin SATA connector.
5.12 Serial ports
Gemini supports 4 serial ports. Each serial port supports RS232, RS485, and RS422 protocol.
The Serial protocol is selectable using jumper settings. The default configuration is RS232. Refer to Jumper configurations for more details
The serial ports are implemented using the XR17V354 PCIe UART transceiver.
The SP336E transceiver converts the UART signals to RS232, RS485, or RS422 based on jumper settings. Max data rate supported is 250kbps with Slew rate tied low and 1Mbps with slew rate tied high.
The RS-232 driver output capability is +/-6.6V. The RS-485/RS-422 Driver Common mode voltage is 3V and the differential driver output is 1.5V to 3.3V. Optional 121-Ohm line terminations for RS485 and RS422. They can be selected by jumper settings.
Refer to section 11 for jumper details.
5.13 Trusted Platform Module
Gemini provides a TPM 2.0 IC SLB 9670XQ2.0 from Infineon accessible through the SPI interface. The TPM 2.0
Meets Intel TXT, Microsoft Windows, and Google Chromebook certification criteria for successful platform qualification
supports Random Number Generator (RNG) according to NIST SP800-90A
supports Full personalization with Endorsement Key (EK) and EK certificate
For enabling TPM functionality TPM 2.0 should be enabled, activated, and set to UEFI from the BIOS screen.
5.14 USB ports
Gemini provides 6 USB ports to the user.
Four ports are USB 2.0 ports. These are accessible on 2 2x5 headers.
Two ports are USB 3.0 ports. These are accessible on 2 2x5 headers.
COMExpress type 6 pinout supports 8 USB2.0 ports from the module. These ports are mapped as follows.
Port | Connector | Assignment |
0 | I/O Connector 1(J16) | Port 1 |
1 | I/O Connector 1(J16) | Port 2 |
2 | I/O Connector 2(J17) | Port 1 |
3 | I/O Connector 2(J17) | Port 2 |
4 | Either USB to GPIO Expander or mPCIe Slot Using a Mux(see section 10 JP3) | |
5 | USB 3.0 Connector 1(J14) | Port 1 |
6 | USB 3.0 Connector 2(J15) | Port 1 |
7 | PCIe/104 Connector(J1) | First Bank |
5.15 PCI-104 and PCIe/104 Expansion Interface
Gemini supports PCI/104-Express expansion. The PCI bus is realized using PCIe-PCI bridge XIO2001 from TI. Both 5V and 3.3V levels are supported on the PCI bus. The voltage level is selectable using Jumper settings.
4 x1 PCIe gen2, x16 PEG and 1 USB2.0 port are supported on PCIe/104 expansion connector.
x16 PEG is module dependant.
5.16 Utility header
The below table lists the features available on the Utility connector:
Sl.No | Interface |
1 | I2C |
2 | Power Button |
3 | Reset Button |
4 | LPC bus |
5 | GbE LEDs(Optional instead of LPC bus) |
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