NEC µPD7720
The NEC μPD7720 is the name of fixed point digital signal processors from NEC (currently Renesas Electronics). Announced in 1980, it became, along with the Texas Instruments , one of the most popular DSPs of its day.
Background[]
In the late 1970s, telephone engineers were attempting to create technology with sufficient performance to enable digital touch-tone dialing.[1] Existing digital signal processing solutions required over a hundred chips and consumed significant amounts of power.[2] Intel responded to this potential market by introducing the Intel 2920, and integrated processor that, while it had both digital-to-analog and analog-to-digital converters, lacked additional features (such as a hardware multiplier) that would be found in later processors.[1] Announcements for the first "real" DSPs, the NEC μPD7720 and the Bell Labs DSP-1 chip, occurred the following year at the 1980 IEEE International Solid-State Circuits conference.[3] The μPD7720 first became available in 1981[4] and commercially available in late 1982 at a cost of US$600 each (approx. $1,600 today).[2] Beyond their initial use in telephony, these processors found applications in disk drive and graphics controllers, speech synthesis and modems.[5]
Architecture[]
Detailed descriptions of the μPD7720 architecture are found in Chance (1990),[6] Sweitzer (1984)[7] and Simpson (1984).[8] Briefly, the NEC μPD7720 runs at 4 MHz frequency with 128-word data RAM, 512-word data ROM, and 512-word program memory, which has VLIW-like instruction format, enabling all of ALU operation, address register increment/decrement operation, and move operation in one cycle.
Variants[]
The NEC μPD77C25, which succeeded the μPD7720, runs at 8 MHz frequency with 256-word data RAM, 1,024-word data ROM, and 2,048-word program memory.
References[]
- ^ Jump up to: a b Hays, W. Patrick (March 2004). "DSPs: Back to the Future". Queue. 2 (1): 44. doi:10.1145/984458.984485. (subscription required)
- ^ Jump up to: a b Tretter, Steven A. (2008). Communication System Design Using DSP Algorithms. Springer. p. 2. ISBN 978-0-387--74885-6.
- ^ Waldner, Jean-Baptsite (2007). Nanocomputers and Swarm Intelligence. Wiley. p. 93. ISBN 978-1-84821-009-7.
- ^ :Anderson, Alexander John (1994). Foundations of Computer Technology. Chapman & Hall. p. 365. ISBN 0-412-59810-8.
- ^ Lee, Edward Ashford; Seshia, Sanjit Arunkumar (2011). Introduction to Embedded Systems: A Cyber-physical Systems Approach. Lee & Seshia. p. 182. ISBN 978-0-557-70857-4.
- ^ Chance, R. J. (1990). "Devices Overview". In Jones, N. B.; Watson, J. D. McK. (eds.). Digital Signal Processing: Principles, Devices and Applications. Peter Peregrinus Ltd. pp. 10–12. ISBN 0863412106.
- ^ Sweitzer, S. (March 1984). "A low cost FFT chip set". IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). 9: 371–373. doi:10.1109/ICASSP.1984.1172726.(subscription required)
- ^ Simpson, Robert J.; Terrell, Trevor J. (September 1984). "Digital filtering using the NEC μPD7720 signal processor". Microprocessing and Microprogramming. 14 (2): 67–78. doi:10.1016/0165-6074(84)90101-7.(subscription required)
External links[]
- Datasheets for the UPD7720A, UPD7720AC and UPD7720AD are available here.
- NEC microprocessors
- Digital signal processors