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The Design of a ISA DSP CARD. by Asher C. Martin Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign Tel: 217-367-3877 e-mail: martin2@uiuc.edu. “Nothing is particularly hard if you divide it into small jobs.” -Henry Ford-.
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The Design of aISA DSP CARD by Asher C. Martin Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign Tel: 217-367-3877 e-mail: martin2@uiuc.edu
“Nothing is particularly hard if you divide it into small jobs.” -Henry Ford-
Project Goals & Introduction • Design of an embedded DSP system from the ground up • DSP card would meet a variety of practical real-world applications • High-speed digital signal processing
Design Specs • DSP I/O Performance: • ADC: 16 bit input resolution at 85 ksps (~76μV) (thousands of samples per-second) • DAC: 8 bit output resolution • Three FPGA’s (run in “parallel” x 3) • 25 MHz • Total of 30 thousand reprogramable gates • ISA BUS Performance: • 8 MHz with 8 bit transfers • 252 + interconnections with nearly 150 ft of wire wrap
Block Diagram SRAM ADC/DAC DSP ISA
How did I test the card? • With nearly 150 ft of wire on a board testing the various components was difficult. • Used the model “keep it simple” and divide my system into the DSP, ISA, and SRAM interfaces.
How does the DSP work? • The DSP is interfaced with all of the other components on the card. • Memory Address Bus - 8 bit (with SRAM) • Memory Data Bus - 8 bit (with SRAM) • Host PC Data Bus - 8 bit (with ISA BUS) • OPCODE Bus - 8 bit (with all FPGA’s) • Two Custom DSP ports • Analog Port (9 pin / Port A) • Digital Port (26 pin / Port B)
DSP Layout SRAM/ISA DATA BUS SRAM ADDRS ADC/DAC INTERFACE DSP FPGA
TWO CUSTOM DSP PORT Physical DSP Interface ADC SRAM/ISA DATA BUS
ISA Bus Interface • Address Bus - 12 bit (with host PC) • Data Bus - 8 bit (with host PC) • “inp/outp” port 380h • (with host PC software) • I/O Address is reprogramable
Interfacing with the ISA bus ISA FPGA ISA BUS
Physical ISA Bus Interface 12 Bit Address 8 Bit Data
Interfacing with the SRAM • Since I couldn’t purchase SRAM from Cypress I had to make my own RAM inside the FPGA. • Address Bus • 8 bit with DSP • Data Bus • 8 bit with DSP DATA BUS ADDRESS BUS
SRAM Interface ADDRESS DATA
DSP Software (GUI) RECIEVE TRANSMIT
Concluding Remarks / Future • “...divide it into small jobs.” -Henry Ford- • Future Additions: • IRQ: Interrupt based I/O with ISA bus • 16 bit ISA I/O transfers • High-performance FPGA’s (200Mhz +) • Improve accuracy of ADC by separating digital and analog grounds.
References • Maxim IC (datasheets) • http://www.maxim-ic.com • Xilinx (hardware/software) • http://www.xilinx.com • ECE Stores • Components suggestions • Lawrence Ronk (ECE 345 TA) • ronk@ews.uiuc.edu