Method and apparatus for serial data flow control
US5179661A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 30, 1989 |
| Grant date | Jan 12, 1993 |
| Priority date | — |
| Expiry date | Oct 30, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L9/40
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A data flow controller (150) for monitoring and automatically controlling the flow of serial data from a remote transmitter to a host device. A serial communications card (11) provides an interface between a remote transmitter connected to a serial port connector (20) and a host device (10). The card (11) contains a UART (14) which has a buffer. A counter (151) counts the number of bytes received by the UART (14) since the last time that the host (10) read all the data in the buffer. If the number exceeds a predetermined portion of the buffer capacity the counter output (Q11) will go high, thereby disabling the counter and sending a control signal (DTR, RTS) to the remote transmitter to stop sending data. Once the host (10) has read all the data in the buffer the UART (14) provides a signal (-RXREADY) which resets the counter (151), thereby causing the output (Q11) to go low, thereby allowing the remote transmitter to resume sending data. The counter (151) is held in a reset state until the buffer has received at least one byte of data. Data flow control is therefore obtained without the intervention of the host (10).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.