Electrical computers and digital data processing systems: input/ – Input/output data processing – Input/output data buffering
Patent
1998-01-22
2000-08-29
Lee, Thomas C.
Electrical computers and digital data processing systems: input/
Input/output data processing
Input/output data buffering
710 52, 710 62, 710 69, 711110, 375222, G06F 1300
Patent
active
061122661
ABSTRACT:
An HSP communication system includes a host computer which executes a software portion of an HSP modem and a device containing a digital-to-analog converter (DAC). In response to interrupts, the host executes an update routine that generates and writes samples to a software circular buffer in memory of the host computer. The samples represent amplitudes of an analog signal complying with a desired communication protocol. A direct transfer moves samples from the software circular buffer to a hardware circular buffer the device, and the DAC converts the samples from the hardware circular buffer into an analog communication signal. In an exemplary embodiment, the hardware portion is coupled to a PCI bus in the host computer, and direct transfers are according to the PCI bus master protocol. In environments such as multi-tasking systems, the host may skip interrupts or otherwise not provide new samples when required. In this case, the direct transfers transfer old samples, and the DAC reuses samples from the software circular buffer to generate a maintenance signal. If direct transfers are delayed, the DAC can reuses samples from the hardware circular buffer to generate the maintenance signal. The maintenance signal typically does not convey correct data but is sufficient to maintain a communication link and prevent a remote device from disconnecting or entering a retrain mode. For a better maintenance signal, the circular buffers contains samples for an integral number of periods of the baud frequency of the desired protocol. Error correction and retransmission can replace incorrect or lost data.
REFERENCES:
patent: 4965641 (1990-10-01), Blackwell et al.
patent: 4972411 (1990-11-01), Fushimi et al.
patent: 4991169 (1991-02-01), Davis et al.
patent: 4995074 (1991-02-01), Goldman et al.
patent: 5375228 (1994-12-01), Leary et al.
patent: 5625845 (1997-04-01), Allran et al.
patent: 5678059 (1997-10-01), Ramaswamy et al.
patent: 5717948 (1998-02-01), Michalina
patent: 5721830 (1998-02-01), Yeh
patent: 5768628 (1998-06-01), Priem
patent: 5892978 (1999-04-01), Munguia et al.
Disclosure Statement By Inventor (signed and dated Nov. 12, 1999).
"PCT1441 Host Signal Processing High Speed Data/Fax/Voice Modem Chip" data sheets (23 pages).
Cao Chun
Lee Thomas C.
Millers David T.
PC-Tel, Inc.
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