The EVAL-CN0585-FMCZ Low Latency Development Kit (LLDK) board is a development board consisting of 4 x 16-bit ADC channels and 4 x 16-bit DAC channels that are interfaced with an FPGA through the FMC Low Pin Count (LPC) Connector. Current revision of EVAL-CN0585-FMCZ is Rev B. EVAL-CN0585-FMCZ, EVAL-CN0584-EBZ and ZedBoard are connected together to build a development system setup as shown in Figure 1..
Figure 1. Development Platform Setup
The EVAL-CN0585-FMCZ board provides a complete data acquisition and signal generation platform with onboard power rails, voltage monitoring, logic level translation, general purpose I/O, I2C, SPI, and an Analog Front End(AFE) board connector.
The key performance benefit of the EVAL-CN0585-FMCZ is the ability to perform a complete capture and conversion of precision analog input data in <70ns with the ADC module and generate a settled full-scale analog output in <200ns from initial data written to the DAC.
Figure 2. EVAL-CN0585-FMCZ Board Top
Figure 3. EVAL-CN0585-FMCZ Board Bottom
Figure 4. EVAL-CN0585-FMCZ Simplified Block Diagram
The EVAL-CN0585-FMCZ board has four ADAQ23876 16Bit 15MSPS Data Acquisition µModules to capture analog data from the AFE board connector. The Data Acquisition µModules are configured to simultaneously sample the four input channels. The data acquired by the ADAQ23876 is routed to the FPGA through the FMC LPC connector using a serial low voltage differential signaling (LVDS) digital interface in a two-lane output mode. The ADAQ23876 has pin configurable input voltage span with configurable gain/attenuation options: 0.37, 0.73, 0.87, 1.38, and 2.25, providing input voltage span ranges of ±10 V, ±5 V, ±4.096 V, ±2.5 V, and ±1.5 V. The gain/attenuation functions are accessible through the AFE board connector pins. As an example the EVAL-CN0584-EBZ is available for Hardware In the Loop (HIL) applications.
The EVAL-CN0585-FMCZ board has two AD3552R 16-bit 33MUPS DACs that provide four analog output signals to the AFE board connector. Data is transferred to the AD3552R DAC from the FPGA through the FMC LPC connector using a Quad-SPI dual data rate interface.
The AD3552R has a pin-configurable output voltage span that can be configured through the AFE board connector. Multiple output span ranges can be configured, such as 0 V to 2.5 V, 0 V to 5 V, −5 V to +5 V, −10 V to +10 V, and custom intermediate ranges with full 16-bit resolution. (Refer to Table 3)
The default ADC reference configuration uses the internal 2.048 V, ±0.1% accurate, 20 ppm/°C max voltage reference. For more stringent use cases where the accuracy and temperature drift is an issue, an external LTC6655 2.048 V, ±0.025% accurate, 2 ppm/°C max voltage reference can be used.
The default DAC reference configuration uses the internal 2.5 V, ±0.3% accurate, 10 ppm/°C max voltage reference. For more stringent use cases where the accuracy and temperature drift is an issue, an external ADR4525 2.5 V, ±0.02% accurate, 2 ppm/°C max voltage reference can be used.
Table 1. Voltage Reference Settings
The EVAL-CN0585-FMCZ board provides voltage monitoring capability for the power supply rails. The circuit consists of an AD7291 8-Channel, I2C, 12-Bit SAR ADC, and resistive dividers. Each power rail is connected to AD7291 by resistive dividers as shown in Figure 5.
Figure 5: Power Supply Voltage Monitor Circuit
The negative power supply rails are biased positive with a buffered 2.5V reference supplied by the AD7291.
Calculating the supply voltage from the positive voltage rails can be accomplished using the following equation:
Calculating the supply voltage from the negative voltage rails can be accomplished using the following equation:
|Monitored Rail||CN0585 Power Rail||Scale Factor||IIO Measured Voltage||Actual Voltage|
|voltage0||+12 V (AD8065 DAC amp)||5.3||2.26 V||11.98 V|
|voltage1||-12 V (AD8065 DAC amp)||-7.81||0.65 V||-11.95 V|
|voltage2||+5 V (ADAQ23876 amp)||2.43||2.06 V||5.00 V|
|voltage3||-5 V (ADAQ23876 amp)||-4.32||0.76 V||-5.02 V|
|voltage4||+5 V (DAC)||2.43||2.06 V||5.00 V|
|voltage5||+5 V (DAC)||2.43||2.06 V||5.00 V|
|voltage6||+2.5 V (digital)||1.11||2.25 V||2.50 V|
|voltage7||+1.8 V (digital)||1||1.80 V||1.80 V|
Table 2. Voltage Scaling
The default I2C address of the AD7291 is 0x20. Resistors R13, R14, R17, and R18 can be used to select alternate addressing.
Several logic-level translators are used on the board to interface with the FMC connector signals and the various logic levels used on the board. The FMC connector signal levels are driven by the VIO voltage supplied from the FPGA board.
A GPIO interface is provided by a MAX7301ATL+ I/O Expander connected to the SPI interface on the SPIO_CSB0 chip select interface. The GPIO outputs are controlled by writing to the MAX7301ATL+ via the SPI interface provided on the FMC connector. Four GPIO signals are utilized on the EVAL-CN0585-FMCZ board to control the power-down interface of the ADAQ23875 Data Acquisition µModules. Eight GPIO signals are level-shifted and provided to the AFE board connector for control signals on the AFE board.
The I2C interface is provided from the FPGA FMC connector and is made available to the EVAL-CN0585-FMCZ board and the user via the AFE board connector. On the EVAL-CN0585-FMCZ board the I2C interface is used to communicate with an EEPROM that is required by the Vita 57.1 Standard for board identification and IO characteristics, and the AD7291 voltage monitoring ADC.
The EVAL-CN0585-FMCZ board provides an SPI interface for the user on SPI0 from the FMC connector. Communication with the MAX7301ATL+ GPIO expander is enabled by chip select SPIO_CSB0. A second chip select, SPI_CSB1 originates from the FMC interface and connects to the AFE board connector so that the user can attach a custom secondary SPI device to the AFE board. This second SPI0_CSB1 is not initialized in the Linux device tree, as the initialization requires additional information such as SPI transmission mode, phase, and polarity. Two Quad-SPI interfaces (DAC0/1 and DAC2/3) are provided by the FMC interface to handle communications and data transfer to the four AD3552R DAC channels.
The AFE connector interface provides six signal connections for each of the four ADAQ23876 Data Acquisition µModules. The six signal connections allow the user to set the input voltage range of the differential amplifier input. Configuration resistors, if used, should be placed as close as possible to the AFE board connector. Please refer to the ADAQ23876 Datasheet for more configuration details.
|Input Range||Input Signal on Pins||Feedback Connections|
|+/- 10V (Default)||ADCx_IN2P, ADCx_IN2N||ADCx_OUTP and ADCx_IN1N pins Shorted ADCx_OUTN and ADCx_IN1P pins Shorted|
|+/- 5V||ADCx_IN1P, ADCx_IN1N||ADCx_OUTP and ADCx_IN2N pins Shorted ADCx_OUTN and ADCx_IN2P pins Shorted|
|+/- 4.096V||ADCx_IN2P, ADCx_IN2N||No Connect|
|+/- 2.5V||ADCx_IN1P, ADCx_IN1N||No Connect|
|+/- 1.5V||ADCx_IN1P/ADCx_IN2P Shorted ADCx_IN1N/ADCx_IN2N Shorted||No Connect|
Table 3: ADQ23876 Connections for Input Configuration
The AFE connector interface provides three signal connections for each of the four DAC output channels. The three signal connections allow the user to set the output voltage range of the AD3552R DAC. Configuration resistors, if used, should be placed as close as possible to the AFE board connector. The AD3552R uses a current steering DAC architecture with a VREF voltage of 2.5 V. The DAC current is converted to a voltage using an external TIA. The DAC outputs are observed on signals DAC0, DAC1, DAC2, and DAC3. The DACx outputs are fed back into the AD3552R gain configuration pins for each DAC channel. The table below details the configuration connections for each of the output voltage ranges of each of the DAC output channels. Please refer to the AD3552R Datasheet for more configuration details.
|Hardware||AD3552R Register Settings|
|Channel||Output Span||VZS (V)||VFS (V)||Feedback Connection||CH0_CH1_OUTPUT_range||CHx_GAIN_SCALING_N||CHx_OFFSET|
|CH0||+/- 10V (Default)||-10.382||10.380||DAC0 to DAC0_RFB0||0x100||0||-245|
|+/- 5V||-5.165||5.166||DAC0 to DAC0_RFB0_X2||0x011||0||-495|
|10V||-0.165||10.163||DAC0 to DAC0_RFB0_X2||0x010||0||495|
|5V||-0.078||5.077||DAC0 to DAC0_RFB0_X1||0x001||0||0|
|2.5V||-0.198||2.701||DAC0 to DAC0_RFB0_X1||0x000||3||-48|
|CH1||+/- 10V (Default)||-10.382||10.380||DAC1 to DAC1_RFB1||0x100||0||-245|
|+/- 5V||-5.165||5.166||DAC1 to DAC1_RFB1_X2||0x011||0||-495|
|10V||-0.165||10.163||DAC1 to DAC1_RFB0_X2||0x010||0||495|
|5V||-0.078||5.077||DAC1 to DAC1_RFB1_X1||0x001||0||0|
|2.5V||-0.198||2.701||DAC1 to DAC1_RFB1_X1||0x000||3||-48|
|CH2||+/- 10V (Default)||-10.382||10.380||DAC2 to DAC2_RFB0||0x100||0||-245|
|+/- 5V||-5.165||5.166||DAC2 to DAC2_RFB0_X2||0x011||0||-495|
|10V||-0.165||10.163||DAC2 to DAC2_RFB0_X2||0x010||0||495|
|5V||-0.078||5.077||DAC2 to DAC2_RFB0_X1||0x001||0||0|
|2.5V||-0.198||2.701||DAC2 to DAC2_RFB0_X1||0x000||3||-48|
|CH3||+/- 10V (Default)||-10.382||10.380||DAC3 to DAC3_RFB1||0x100||0||-245|
|+/- 5V||-5.165||5.166||DAC3to DAC3_RFB1_X2||0x011||0||-495|
|5V||-0.078||5.077||DAC3 to DAC3_RFB1_X1||0x001||0||0|
|2.5V||-0.198||2.701||DAC3 to DAC3_RFB1_X1||0x000||3||-48|
Table 4: AD3552R Connections for Output Configuration
The AFE board connector provides an input/output interface to the EVAL-CN0585-FMCZ board. The interface provides connections to the analog IO, ADC/DAC gain settings, GPIO, I2C, SPI, aux power, and four direct FMC connections to allow system flexibility interfacing with custom AFE designs that are provided by ADI or can be custom designed by the user. Currently, ADI provides the EVAL-CN0584-EBZ as an analog front-end board.
The AFE board connector on the EVAL-CN0585-FMCZ board is a Samtec High-Density socket connector.
FMC LPC connector routes the data acquired by the ADAQ23876 to FPGA and transfers the data from FPGA to AD3552R DAC.
Figure 6. FMC LPC Connector Pinout
Once the board is connected to the host, and power is delivered, the green LED DS1 should be on.
The Rev. B of the EVAL-CN0585-FMCZ board is powered through the USB-C connector of the board.
The EVAL-CN0585-FMCZ(Rev B) (connected to EVAL-CN0584-EBZ) is fully supported using a ZedBoard. For description of system setup and functionality using EVAL-CN0584-EBZ, EVAL-CN0585-FMCZ and ZedBoard, refer to CN0584 User Guide, System Setup Using a ZedBoard section.