CDB5529 CDB5529 Evaluation Board and Software Features General Description The CDB5529 is an inexpensive tool designed to evalu- l RS-232 Serial Communication with PC ate the performance of the CS5529 16-bit Analog-to- l On-board 80C51 Microcontroller Digital Converter (ADC). l On-board Voltage Reference The evaluation board includes an LT1019 voltage refer- ence, an 80C51 microcontroller, an RS232 TM l Lab Windows/CVI Evaluation driver/receiver, and firmware. The 8051 controls the se- Software rial communication between the evaluation board and the PC via the firmware, thus, enabling quick and easy - Register Setup & Chip Control access to all of the CS5529s registers. - FFT Analysis The CDB5529 also includes software for Time Domain - Time Domain Analysis Analysis, Histogram Analysis, and Frequency Domain - Noise Histogram Analysis Analysis. l Integrated RS-232 Test Mode ORDERING INFORMATION: CDB5529 +5/+2.5 ANALOG -2.5 ANALOG AGND DGND +5/3.3 DIGITAL +5 DIGITAL RS232 CONNECTOR VOLTAGE REFERENCE LEDs RS232 J1 DRIVER/RECEIVER CS5529 REF+ AIN+ AIN+ 80C51 MICROCONTROLLER AIN- AIN- CS REF- SDI SDO RESET CRYSTAL SCLK CIRCUITRY 11.0592MHz D3 D2 D1 TEST D0 A1 SWITCHES A0 XOUT XIN HDR6 CRYSTAL 32768Hz Cirrus Logic, Inc. Copyright Cirrus Logic, Inc. 1997 AUG 97 Crystal Semiconductor Products Division (All Rights Reserved) P.O. Box 17847, Austin, Texas 78760 DS246DB1 (512) 445 7222 FAX: (512) 445 7581 1 CDB5529 The evaluation board provides two voltage refer- PART I: HARDWARE ence options, on-board and external. With HDR5s Introduction jumpers in positions 1 and 4, the LT1019 provides an absolute voltage level of 2.5 volts (the LT1019 The CDB5529 evaluation board provides a quick was chosen for its low drift, typically 5ppm/C). By means of testing the CS5529 Analog-to-Digital setting HDR5s jumpers to position 2 and 3, the Converter (ADC). The board interfaces the TM user can supply an external voltage reference to CS5529 to an IBM compatible PC via an J1s REF+ and REF- inputs (Application Note 4 on RS-232 interface while operating from either a sin- Crystal Semiconductors web site details various gle +5 V supply or dual 2.5 volt supplies. To ac- voltage references). complish this, the board comes equipped with an TM 80C51 microcontroller and a 9-pin RS-232 cable The ADC serial interface is SPI and TM which physically interfaces the evaluation board to MICROWIRE compatible. The interface control the PC. Additionally, analysis software provides lines (CS, SDI, SDO, and SCLK) are connected to easy access to the internal registers of the convert- the 80C51 microcontroller via port one. To inter- er, and provides a means to display the converters face an external microcontroller, these control lines time domain, frequency domain, and noise histo- are also connected to HDR6. However to accom- gram performance. The evaluation boards soft- plish this, the evaluation board must be modified in ware includes debug algorithms to trouble shoot one of three ways: 1) cut the interface control traces the evaluation board. Refer to the Trouble Shoot- going to the microcontroller, 2) remove resistors ing the Evaluation Board section for more details. R1-R8, or 3) remove the microcontroller. Evaluation Board Overview Figure 2 illustrates the schematic of the digital sec- tion. It contains the microcontroller, a Motorola The board is partitioned into two sections: analog MC145407 interface chip, and test switches. The and digital. The analog section consists of the test switches aid in debugging communication CS5529 and a precision voltage reference. The dig- problems between the CDB5529 and the PC. The ital section consists of the 80C51 microcontroller, microcontroller derives its clock from an 11.0592 the hardware test switches, the reset circuitry, and MHz crystal. From this, the controller is configured the RS-232 interface. to communicate via RS-232 at 9600 baud, no pari- The CS5529 is designed to digitize signals while ty, 8-bit data, and 1 stop bit. operating from a 32.768 KHz crystal. As shown in Figure 1, a signal can be connected to the convert- ers inputs via J1s AIN+ and AIN- inputs. Note that a simple RC network filters the input to reduce broadband noise. 2 DS246DB1