Datasheet

Detailed Description of Hardware
Fremont interfaces with field-programmable gate array (FPGA) development
boards using a Pmod connector. The Pmod specification allows for both 3.3V
and 5V modules as well as various pin assignments. Fremont requires a 3.3V
supply voltage and uses the SPI pin assignments as illustrated here.
Table 1 shows the power requirements. Table 2 shows the supported platforms
and ports.
Table 1. Power Requirement for the Fremont Subsystem Reference
Design
Power Type Input
Input Voltage
(V)
Input Current (mA,
typ)
External
power
EXT_V+ 7 22
EXT_V- -6 20
Table 2. Supported Platforms and Ports
Supported Platforms Ports
Nexys
™
3 platform (Spartan
®
-6)
JB1
ZedBoard
™
platform (Zynq
®
-7020)
JA1
The MAX9632 (U1) op amp input circuit amplifies and buffers a 0 to100mV signal to match the input range of the
ADC (MAX11100), which is 0 to 4.096V.
The MAX11100 (U2) is a 16-bit, successive-approximation register (SAR) ADC with AutoShutdown
™
and fast
1.1µs wake-up features. The ADC’s reference input is driven by an ultra-high-precision 4.096V voltage reference,
the MAX6126 (U3), with 0.02% initial accuracy and a 3ppm/°C maximum temperature coefficient (tempco).
The Fremont hardware design provides isolated data (MAX14850) for a high-accuracy, high-impedance, 0 to
100mV signal, analog-to-digital conversion application.
External power supplies power the Fremont board prior to voltage regulation. The MAX1659 LDO regulator
provides +6V and +5V rails and the MAX1735 LDO regulator provides the -5V rail. The MAX14850 (U5) isolates
the digital data up to 600V.
To power the Fremont board, connect the ground terminal of the external power supplies to the GND2 connector.
Connect the +7V to +16.5V supply to the EXT_V+ connector, and the -6V supply to the EXT_V- connector.
Detailed Description of Firmware for Nexys 3 Platform
Table 2 shows currently supported platforms and ports. Support for additional platforms may be added
periodically under Firmware Files in the All Design Files section below.
The Fremont firmware released for the Nexys 3 development kit targets a Microblaze
™
soft-core microcontroller
placed inside a Xilinx
®
Spartan-6 FPGA.
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