4.1.1.5. STEMlab 125-14 4-Input

../../../_images/STEMlab-125-14-4-Input.jpg

STEMlab 125-14 4-Input is a single-board RF signal acquisition platform that offers the same general hardware features as STEMlab 125-14. The main differences/benefits are that:

  • There are 4 analog input channels @ 125 Msps & 14 bits (instead of 2 inputs and 2 outputs).

  • RF inputs come with better performance (less crosstalk, noise, and distortions).

  • Zynq 7020 (bigger FPGA that offers more processing capabilities and more digital IO pins available on the extension connector).

  • Switching between internal and external clocks can be done using a jumper or control signal on the extension connector. Connect the CLK_SEL pin to GND for the board to switch to EXT clock and to 3V3 (Vcc) to use the internal clock.

Note

Booting without the external clock present? When the CLK_SEL pin is driven to GND, the official Red Pitaya OS will not boot without providing an external clock as it relies on reading the FPGA register map, which is available if the ADC clock is present. However, by modifying the software, the Linux OS itself can boot even without the external clock present, but please note it will crash when trying to read from the FPGA without the external clock present.

4.1.1.5.1. Pinout

../../../_images/Red_Pitaya_pinout.jpg

4.1.1.5.2. Technical specifications

Basic

Processor

DUAL CORE ARM CORTEX A9

FPGA

FPGA Xilinx Zynq 7020 SOC

RAM

512 MB (4 Gb)

System memory

Micro SD up to 32 GB

Console connection

Micro USB

Power connector

Micro USB

Power consumption

5 V, 2 A max

Connectivity

Ethernet

1 Gbit

USB

USB 2.0

Wi-Fi

requires Wi-Fi dongle

RF inputs

RF input channels

4

Sample rate

125 MS/s

ADC resolution

14 bit

Input impedance

1 MΩ / 10 pF

Full scale voltage range

±1 V (LV) and ±20 V (HV)

Input coupling

DC
Absolute max. Input
voltage range
LV +-6 V
HV +-30 V

Input ESD protection

Yes

Overload protection

Protection diodes

Bandwidth

DC - 60 MHz

RF outputs

RF output channels

N/A

Sample rate

N/A

DAC resolution

N/A

Load impedance

N/A

Voltage range

N/A

Short circuit protection

N/A

Connector type

N/A

Output slew rate

N/A

Bandwidth

N/A

Extension connector

Digital IOs

22

Digital voltage levels

3.3 V

Analog inputs

4

Analog inputs voltage range

0 - 3.5 V

Analog input resolution

12 bit

Analog input sample rate

100 kS/s

Analog outputs

4

Analog outputs voltage range

0 - 1.8 V

Analog output resolution

8 bit

Analog output sample rate

≲ 3.2 MS/s

Analog output bandwidth

≈ 160 kHz

Communication interfaces

I2C, SPI, UART, CAN

Available voltages

+5 V, +3.3 V, -4 V

External ADC clock

Yes

Synchronisation

External trigger input

Through E1 ext. connector (DIO0_P)

External trigger input impedance

High-Z (digital input)

Trigger output 1

Through E1 ext. connector (DIO0_N)

Daisy chain connection

Over SATA connection (up to 500 Mbps)

Ref. clock input

N/A

Footnotes

1

See the Click Shield synchronisation section and Click Shield synchronisation example.

Note

For more information, please refer to the Product comparison table.

Note

Jumper orientation can affect the measurements taken with Red Pitaya. Check the Jumper Orientation for more details.

4.1.1.5.3. Switching between internal and external clock

Driving the CLK_SEL pin to GND (logic 0) switches the board to external clock mode. When the pin is driven to 3V3 (logic 1) or left floating, the board operates in the internal clock mode (on-board oscillator).

When STEMlab 125-14 4-Input is in External clock mode the ADC clock must be provided from an external source clock. An external clock should be connected to the Ext ADC CLK- and + pins. According to the ADC spec, external clock signal levels should be LVDS in the range from 1 MHz to 125 MHz.

Note

In the External clock mode, the OS will not boot without providing an external clock.

4.1.1.5.4. Schematics

4.1.1.5.5. Mechanical Specifications and 3D Models

4.1.1.5.6. Extension connector STEMlab 125-14 4-Input

  • Available voltages: +5 V, +3.3 V, -3.4 V

  • Current limitations:

    • 500 mA for +5 V (to be shared between extension module and USB devices)

    • 500 mA for +3V3 (to be shared between extension module and USB devices)

    • 50 mA for -3V4 supply

4.1.1.5.6.1. Extension connector E1

  • 3V3 power source

  • 22 single ended or 8 differential digital I/Os with 3.3 V logic levels

  • 2 CAN busses

Pin

Description

FPGA pin number

FPGA pin description

Voltage levels

1

3V3

2

3V3

3

DIO0_P / EXT TRIG

G17

IO_L16P_T2_35

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 / CAN1_RX

K16

IO_L24P_T3_AD15P_35

3.3V

16

DIO6_N / CAN1_TX

J16

IO_L24N_T3_AD15N_35

3.3V

17

DIO7_P / CAN0_RX

M14

IO_L23P_T3_35

3.3V

18

DIO7_N / CAN0_TX

M15

IO_L23N_T3_35

3.3V

19

DIO8_P

Y9

IO_L14P_T2_SRCC_13

3.3V

20

DIO8_N

Y8

IO_L14N_T2_SRCC_13

3.3V

21

DIO9_P

Y12

IO_L20P_T3_13

3.3V

22

DIO9_N

Y13

IO_L20N_T3_13

3.3V

23

DIO10_P

Y7

IO_L13P_T2_MRCC_13

3.3V

24

DIO10_N

Y6

IO_L13N_T2_MRCC_13

3.3V

25

GND

26

GND

Note

To change the functionality of DIO6_P, DIO6_N, DIO7_P and DIO7_N from GPIO to CAN, please modify the housekeeping register value at address 0x34. For further details, please refer to the FPGA register section.

The change can also be performed with the appropriate SCPI or API command. Please refer to the CAN commands section for further details.

All DIOx_y pins are LVCMOS33, with the following abs. max. ratings:

  • min. -0.40 V

  • max. 3.3 V + 0.55 V

  • < 8 mA drive strength

4.1.1.5.6.2. Extension connector E2

  • +5 V, -3V4 power sources

  • SPI, UART, I2C

  • 4 slow ADCs

  • 4 slow DACs

  • Ext. clock for fast ADC

Pin

Description

FPGA pin number

FPGA pin description

Voltage levels

1

+5V

2

-3V4

3

SPI (MOSI)

E9

PS_MIO10_500

3.3 V

4

SPI (MISO)

C6

PS_MIO11_500

3.3 V

5

SPI (SCK)

D9

PS_MIO12_500

3.3 V

6

SPI (CS)

E8

PS_MIO13_500

3.3 V

7

UART (TX)

D5

PS_MIO8_500

3.3 V

8

UART (RX)

B5

PS_MIO9_500

3.3 V

9

I2C (SCL)

B9

PS_MIO50_501

3.3 V

10

I2C (SDA)

B13

PS_MIO51_501

3.3 V

11

Ext com.mode

GND (default)

12

GND

13

Analog Input 0

B19, A20

IO_L2P_T0_AD8P_35, IO_L2N_T0_AD8N_35

0-3.5 V

14

Analog Input 1

C20, B20

IO_L1P_T0_AD0P_35, IO_L1N_T0_AD0N_35

0-3.5 V

15

Analog Input 2

E17, D18

IO_L3P_T0_DQS_AD1P_35, IO_L3N_T0_DQS_AD1N_35

0-3.5 V

16

Analog Input 3

E18, E19

IO_L5P_T0_AD9P_35, IO_L5N_T0_AD9N_35

0-3.5 V

17

Analog Output 0

T10

IO_L1N_T0_34

0-1.8 V

18

Analog Output 1

T11

IO_L1P_T0_34

0-1.8 V

19

Analog Output 2

P15

IO_L24P_T3_34

0-1.8 V

20

Analog Output 3

U13

IO_L3P_T0_DQS_PUDC_B_34

0-1.8 V

21

CLK SEL

3.3 V

22

GND

23

Ext Adc CLK+

LVDS

24

Ext Adc CLK-

LVDS

25

GND

26

GND

Note

UART TX (PS_MIO08) is an output only. It must be connected to GND or left floating at power-up (no external pull-ups)!

4.1.1.5.7. Other specifications

For all other specifications please refer to the common hardware specifications.