| [[hardware]] |
| == icE1usb Hardware |
| |
| The icE1usb Hardware consists of a single circuit board (in an optional |
| enclosure). |
| |
| It's main building blocks are: |
| |
| * an iCE40 FPGA |
| * Two E1 line interface (transformers, biasing networks and ESD protection) footnote:[Only one E1 line supported by firmware so far] |
| * a GPS receiver module with 1PPS output to the FPGA footnote:[GPS-DO supported by firmware yet] |
| |
| === Schematics |
| |
| As icE1usb is an OSHW (Open Source Hardware) project, the full schematics |
| and design files are publicly available. |
| |
| The design files in KiCAD formwa are available at https://git.osmocom.org/osmo-e1-hardware/tree/hardware/icE1usb |
| |
| PDF rendered schematics are available at https://git.osmocom.org/osmo-e1-hardware/plain/hardware/icE1usb/r1.0/icE1usb.pdf |
| |
| === Connectors |
| |
| ==== X5A and X5B: E1 Interface Connectors |
| |
| On one side of the PCB there are two RJ45 connectors next to each other. |
| |
| Those are the two E1 line interfaces. The interfaces are of symmetric |
| 120 Ohms type. |
| |
| Assuming the board is oriented with the tab of the RJ45 connectors facing |
| up: |
| |
| * Interface 0 is on the right side |
| * Interface 1 is on the left side (next to the button) |
| |
| The pin-out of the connectors can be swapped between TE and NT mode using |
| the J4 and J5 jumper blocks on the circuit board. |
| |
| A GSM BTS typically implements TE pin-out, while the icE1usb should then |
| use NT mode pin-out if no cross-over cable is used. |
| |
| .Pin-out of RJ45 E1 connectors |
| [options="header"] |
| |=== |
| | Pin | Function (TE) | Function (NT Mode) |
| | 1 | Rx | Tx |
| | 2 | Rx | Tx |
| | 3 | not used | not used |
| | 4 | Tx | Rx |
| | 5 | Tx | Rx |
| | 7 | not used | not used |
| | 8 | not used | not used |
| |=== |
| |
| NOTE: E1 cables use RJ45 like Ethernet, but Ethernet cables have a |
| different pin-out. Particularly, you cannot use an Ethernet cross-over |
| cable as an E1 cross-over! |
| |
| ==== X4: USB Connector |
| |
| The USB connector is a USB Type C connector. However, it only carries |
| USB 1.1 full-speed signals. 5V DC power is also sourced from this |
| connector. |
| |
| ==== X2: Serial Console Connector |
| |
| The serial console is used for development and debugging. It uses an |
| Osmocom-style 2.5mm stereo TRS jack. |
| |
| The serial console uses 3.3V CMOS logic levels |
| |
| The serial console uses a rate of 1000000 bps. |
| |
| The pin-out is as follows: |
| |
| * Tip: Tx output from PC (Rx input of icE1usb) |
| * Ring: Rx input of PC (Tx output of icE1usb) |
| * Shield: GND |
| |
| A compatible cable can be sourced from the sysmocom web-shop at |
| http://shop.sysmocom.de/. |
| |
| ==== X1: GPS Antenna Connector |
| |
| The GPS antenna connector is a female SMA connector. |
| |
| You can connect most standard active GPS antennas with built-in LNA. |
| |
| icE1us provide phantom voltage. |
| |
| The use of a GPS antenna is only required when you need a high precision |
| clock reference for the 2.048 MHz E1 bit clock, e.g. to provide a clock |
| reference to a cellular base station on the A-bis interface. |
| |
| ==== X3: GPIO / Extension Connector |
| |
| This is a RJ45 connector adjacent to the USB connector. |
| |
| It is currently unused and reserved for future use. |
| |
| |
| [[hw-pushbutton]] |
| === Pushbutton |
| |
| This is a push-button next to the _E1 interface '1'_. It is recessed |
| to protect against accidental use. You will need to use a paper clip, |
| pen tip or other similar object to push it. |
| |
| The button can be used to force booting into the DFU loader in order to |
| recover from a broken firmware installation. |
| |
| |
| === Multi-Color LED |
| |
| Above the USB-C connector, there is a multi-color RGB LED. |
| |
| This LED is used by the firmware to indicate a variety of status |
| information. Pleas see the firmware documentation in <<firmware>>. |