Extension Extension connector

  • Connector: 2 x 26 pins IDC (M)
  • Power supply:
  • Available voltages: +5V, +3.3V, 3.3V
  • Current limitations: 500 mA for +5V and +3.3V (to be shared between extension module and USB devices), 50 mA for 3.3V supply. Extension connector E1

  • 3v3 power source
  • 16 single ended or 8 differential digital I/Os with 3,3V logic levels
Pin Description FPGA pin number FPGA pin description Voltage levels
1 3V3      
2 3V3      
3 DIO0_P G17 IO_L16P_T2_35 (EXT TRIG) 3.3V
4 DIO0_N G18 IO_L16N_T2_35 3.3V
5 DIO1_P H16 IO_L13P_T2_MRCC_35 3.3V
6 DIO1_N H17 IO_L13N_T2_MRCC_35 3.3V
7 DIO2_P J18 IO_L14P_T2_AD4P_SRCC_35 3.3V
8 DIO2_N H18 IO_L14N_T2_AD4N_SRCC_35 3.3V
9 DIO3_P K17 IO_L12P_T1_MRCC_35 3.3V
10 DIO3_N K18 IO_L12N_T1_MRCC_35 3.3V
11 DIO4_P L14 IO_L22P_T3_AD7P_35 3.3V
12 DIO4_N L15 IO_L22N_T3_AD7N_35 3.3V
13 DIO5_P L16 IO_L11P_T1_SRCC_35 3.3V
14 DIO5_N L17 IO_L11N_T1_SRCC_35 3.3V
15 DIO6_P K16 IO_L24P_T3_AD15P_35 3.3V
16 DIO6_N J16 IO_L24N_T3_AD15N_35 3.3V
17 DIO7_P M14 IO_L23P_T3_35 3.3V
18 DIO7_N M15 IO_L23N_T3_35 3.3V
19 NC      
20 NC      
21 NC      
22 NC      
23 NC      
24 NC      
25 GND      
26 GND      

All DIOx_y pins are LVCMOS33. abs. max. ratings are: min. –0.40V max. 3.3V + 0.55V Extension connector E2

  • +5V & -3V3 power source
  • SPI, UART, I2C
  • 4 x slow ADCs
  • 4 x slow DACs
  • Ext. clock for fast ADC
Pin Description FPGA pin number FPGA pin description Voltage levels
1 +5V      
2 -3.4V (50mA)1      
3 SPI(MOSI) E9 PS_MIO10_500 3.3V
4 SPI(MISO) C6 PS_MIO11_500 3.3V
5 SPI(SCK) D9 PS_MIO12_500 3.3V
6 SPI(CS#) E8 PS_MIO13_500 3.3V
7 UART(TX) C8 PS_MIO08 3.3V
8 UART(RX) C5 PS_MIO09 3.3V
9 I2C(SCL) B9 PS_MIO50_501 3.3V
10 I2C(SDA) B13 PS_MIO51_501 3.3V
11 Ext com.mode     GND (default)
12 GND      
13 Analog Input 0     0-3.5V
14 Analog Input 1     0-3.5V
15 Analog Input 2     0-3.5V
16 Analog Input 3     0-3.5V
17 Analog Output 0     0-1.8V
18 Analog Output 1     0-1.8V
19 Analog Output 2     0-1.8V
20 Analog Output 3     0-1.8V
21 GND      
22 GND      
23 Ext Adc CLK+     LVDS
24 Ext Adc CLK-     LVDS
25 GND      
26 GND      

1 Red Pitaya Version 1.0 has -3.3V on pin 2. Red Pitaya Version 1.1 has -3.4V on pin 2. Schematics of extension connectors is shown in picture bellow.



  1. Input capacitance depends on jumper settings and may vary.
  2. A 50 Ω termination can be connected through an SMA tee in parallel to the input for measurements in a 50 Ω system.
  3. Crosstalk measured with high gain jumper setting on both channels. The SMA connectors not involved in the measurement are terminated.
  4. Measurement referred to high gain jumper setting, with limited environmental noise, inputs and outputs terminated, output signals disabled, PCB grounded through SMA ground. The specified noise floor measurement is calculated from the standard deviation of 16k contiguous samples at full rate. (Typically full bandwidth std(Vn) < 2 mV). Noise floor specification does not treat separately spurious spectral components and represents time domain noise average referred to a 1 Hz bandwidth. In presence of spurious components the actual noise floor would result lower.
  5. Measurement referred at high gain jumper setting, inputs matched and outputs terminated, outputs signal disabled, PCB grounded through SMA ground.
  6. Measurement referred to high gain jumper setting, inputs and outputs terminated, outputs signal disabled, PCB grounded through SMA ground.
  7. Further corrections can be applied through more precise gain and DC offset calibration.
  8. Default software enables sampling at CPU dependent speed. The acquisition of sequence at 100 ksps rate requires the implementation of additional FPGA processing.
  9. First order low pass filter implementation. Additional filtering can be externally applied according to application requirements.
  10. The output channels are designed to drive 50 Ω loads. Terminate outputs when channels are not used. Connect parallel 50 Ω load (SMA tee junction) in high impedance load applications.
  11. Measured at 10 dBm output power level
  12. Typical power level with 1 MHz sine is 9.5 dBm. Output power is subject to slew rate limitations.
  13. Detailed scheme available within documentation (Red_Pitaya_Schematics_v1.0.1.pdf)
  14. To avoid speed limitations on digital General Purpose Input / Output pins are directly connected to FPGA. FPGA decoupling and pin protection is to be addressed within extension module designs. User is responsible for pin handling.
  15. The use of not approved power supply may deteriorate performance or damage the product.
  16. Heatsink must be installed and board must be operated on a flat surface without airflow obstructions. Operation at higher ambient temperatures, lower pressure conditions or within enclosures to be addressed by means of adequate ventilation. The operation of the product is automatically disabled at increased temperatures.
  17. Some parts may become hot during and after operation. Do not touch them.
  18. Measurement performance is specified within this range.
  19. Valid for low frequency signals. For input signals that contain frequency components beyond 1 kHz, the full scale value defines the maximum admissible input voltage.
  20. Jumper settings are limited to the positions described in the user manual. Any other configuration or use of different jumper type may damage the product.
  21. SMA connectors on the cables connected to Red Pitaya must correspond to the standard MILC39012. It’s Important that central pin is of suitable length, otherwise the SMA connector installed in Red Pitaya will mechanically damage the SMA connector. Central pin of the SMA connector on Red Pitaya will loose contact to the board and the board will not be possible to repair due to the mechanical damage (separation of the pad from the board).
  22. Jumpers are not symmetrical, they have latches. Always install jumpers with the latch on its outer side in order to avoid problems with hard to remove jumpers.
  23. Dimensions are rounded to the nearest millimeter. For exact dimensions, please see the Technical drawings and product model. (Red_Pitaya_Dimensions_v1.0.1.pdf)

Information furnished by Red Pitaya d.d. is believed to be accurate and reliable. However, no responsibility is assumed for its use. Contents may be subject to change without any notice. Auxiliary analog input channels

  • Number of channels: 4
  • Nominal sampling rate: 100 ksps (H)
  • ADC resolution 12 bits
  • Connector: dedicated pins on IDC connector E2 (pins 13,14,15,16)
  • Input voltage range: 0 to +3.5 V
  • Input coupling: DC Auxiliary analog output channels

  • Number of channels: 4
  • Output type: Low pass filtered PWM (I)
  • PWM time resolution: 4ns (1/250 MHz)
  • Connector: dedicated pins on IDC connector E2 (pins 17,18,19,20) v - Output voltage range: 0 to +1.8 V
  • Output coupling: DC General purpose digital input/output channels: (N)

  • Number of digital input/output pins: 16
  • Voltage level: 3.3 V
  • Direction: configurable
  • Location: IDC connector E1 (pins 324 ) Powering Red Pitaya through extension connector

Red Pitaya can be also powered through pin1 of the extension connector E2, but in such case external protection must be provided by the user in order to protect the board!


Protection circuit between +5V that is provided over micro USB power connector and +5VD that is connected to pin1 of the extension connector E2. Extension modules

Red Pitaya software and hardware modules enabling the access to and control of auxiliary digital and analog signals

Preliminary design specifications:
  • 16 bidirectional digital I/O lines with individual direction control and 3-state outputs for flexible digital signal acquisition and generation
  • Up to 420 Mbps (voltage level dependent)
  • 16 k samples buffer
  • Advanced triggering schemes for sequence acquisition
  • Integrated level translator functionality for 1.2 V, 1.5V, 1.8V, 2.5V, 3.3V, 5V
  • FPGA ESD protection
  • Additional analog signal filtering
  • General purpose 7 segment numerical display and switches (main purpose: reference voltage setting)
  • Protocol analyser functionality: (to be defined)
  • Integration into Graphical User Interface
  • 4 input and 4 output analogue lines – extension of the analogue pins from Red Pitaya to the extension module

Figure: Proposal for hardware extension module template.


Figure: Connectivity option – 20 pins.


Figure: Possible implementation of some functionality (preliminary version).


Figure: Option - forced air flow.

External links: