EEM - sinara-hw/meta GitHub Wiki
Eurocard Extension Modules
Eurocard Extension Module (EEM) is a Sinara standard for low-cost, low-bandwidth peripherals.
EEM peripherals are supplied with power and a digital interface from an EEM Carrier, such as Kasli, via ribbon cables using the EEM Connector interface. A CompactPCI backplane is being developed as an alternative to the ribbon cables.
Small system example
EEM Carriers
EEM Carriers provide EEM Connectors to supply EEM peripherals with power and digital IO. Presently, Sinara includes two EEM Carriers:
- Kasli Carrier can serve as a stand-alone ARTIQ Master that generates real-time signals
- VHDCI Carrier interfaces with Sayma or Metlino boards that generate real-time signals
EEM Connectors
EEM connectors provide a standardized means of connecting EEM peripherals to a carrier, such as Kasli, which provides power and real-time digital IO.
Connectors are 2x15 100mil pitch male pin-header (pinout below). Wiring between boards is typically done using ribbon cable (50mil wire pitch).
Connector pinout:
| Function | Comment | Pin(s) | pin designation if used for SPI | RJ45 SPI |
|---|---|---|---|---|
| GND | 1, 4, 7, 10, 13, 16, 19, 22, 25 | |||
| +12V | 2A max (5A max for all EEM+Kasli/VHDCI together) | 28, 29 | ||
| +3V3 | 20mA max, managmenet power for EEPROMs etc | 30 | ||
| I2C | 3V3 LVCMOS | 26 (SDA), 27 (SCL) | ||
| LDVS_1 | LVDS, bi-directional | 2 (P), 3 (N) | SCLK0, clock-capable | SCLK0, clock-capable |
| LDVS_2 | LVDS, bi-directional | 5 (P), 6 (N) | MOSI | MOSI0 |
| LDVS_3 | LVDS, bi-directional | 8 (P), 9 (N) | MISO | MISO0 |
| LDVS_4 | LVDS, bi-directional | 11 (P), 12 (N) | CS0 | CS0 |
| LDVS_5 | LVDS, bi-directional | 14 (P), 15 (N) | CS1 | SCLK1 |
| LDVS_6 | LVDS, bi-directional | 17 (P), 18 (N) | MOSI1 | |
| LDVS_7 | LVDS, bi-directional | 20 (P), 21 (N) | MISO1 | |
| LDVS_8 | LVDS, bi-directional | 23 (P), 24 (N) | CS1 |
| odd | even | ||
|---|---|---|---|
| 1 | GND | 0P | 2 |
| 3 | 0N | GND | 4 |
| 5 | 1P | 1N | 6 |
| 7 | GND | 2P | 8 |
| 9 | 2N | GND | 10 |
| 11 | 3P | 3N | 12 |
| 13 | GND | 4P | 14 |
| 15 | 4N | GND | 16 |
| 17 | 5P | 5N | 18 |
| 19 | GND | 6P | 20 |
| 21 | 6N | GND | 22 |
| 23 | 7P | 7N | 24 |
| 25 | GND | SDA | 26 |
| 27 | SCL | 12V | 28 |
| 29 | 12V | MP | 30 |
LVDS is compatible with 1.8V, 2.5 and 3.3V bank supply. Metlino utilizes 1.8V FPGA bank supply, while Kasli utilizes 2.5V supply.
Each EEM peripheral has an EEPROM on its I2C bus for identification.
Digikey has those 30 pins IDC ribbons as assemblies M3DDA-3018J-ND. The use of the strain relief is debatable. It increases assembly height beyond 4HP.
Basic SI testing for Kasli with long EEM cables.
A potential v2 revision of the EEM connector has been discussed here.
EEM Connector Protocol
Multiple digital IO protocols are supported for the LVDS lines on each EEM Connector. Protocol choice is baked-in when the ARTIQ Master FPGA's bitstream is compiled.
- TTLs, input, output, bidirectional
- SPI
- SPI Phys have the pin assignment: SCLK, MOSI, MISO, CS in that order.
- NU-Servo fast ADC/DDS/PID
- CameraLink
See ARTIQ #823 for the bitstream and device_db building infrastructure requirements.
The old idea of having a restricted set of protocols that could be chosen at runtime (see issue #164 for discussion) has been abandoned.
EEM Mechanical
EEM peripheral PCBs are
- 100 mm tall
- up to 160 mm long
- card pitch is 8 HP ("wide") or 4 HP ("narrow").
Thermal/Power
A 10x16 cm board, standing upright can safely dissipate about 5 W through natural convection. Boards dissipating significantly more will likely need forced air flow.
A board can draw up to 2A from its EEM connector via ribbon cable, and 5A from a barrel connector.
Mean Well GSM90B12-P1M are some decent power supplies. They are floating (IEC 320-C8 cord with the narrow Euro plug, doubly insulated Class II devices), "medical", and on the lower side in terms of ripple.
Sanken HWB are some "enclosed" chassis-mount modules that have extremely low ripple for an SMPS and high efficiency.
EEM Chassis/Enclosures
EEM PCBs are designed to mount either in a stand-alone enclosure or in a 19" rack.
Standard open 3U DIN sub-racks/crates ("Baugruppenträger") Fischer 10025291 work well. As do small cases like PROMA 133061 10" or PROMA 133063 19"
System Recommended by @jbqubit (Issue 188):
| Descriptor | Manufacturer | Cost | P/N | Qty | Extended |
|---|---|---|---|---|---|
| Fan tray | Tripp Lite | $130/ea | SRFAN1U | 1 | Rack Enclosure Server Cabinet 1U Cooling Fan Tray 3 120V |
| Rack | Vector Electronics | $225/ea | CCA72-84-01 | 1 | pre-assembled 3U rack |
| Card guides | Vector Electronics | $19/ea | CG3-160/12 | 4 | 160 mm card guide pkg of 12 |
| 1U blanks | Rosewill | $15/ea | RSA-1UPA003 | 2 | 1U 19 Inch Horizontal Metal Blank Panel with Vented slots |
| 12 V supply | Digi-Key | $30/ea | AKM65US12 (1470-4452-ND) | 1 | AC-DC adapter |
CompactPCI Serial Backplane
The CompactPCI Serial standard has been chosen as backplane for EEM based on an existing COTS platform.
Initial specification of the CPCIS ecosystem is described here with further discussion here. Existing EEM modules can be used with CPCIS backplane using CompactPCI Serial 2 EEM Adapter. Standard CPCIS backplane constraints to only 4HP modules, so 84HP full-width backplane is being specified.