Error-tolerant video display subsystem
AssigneeLSI Logic Corporation
InventorGregg Dierke
Life of this patent
Estimating the term…
Abstract
A Video Display FIFO includes a circular buffer and counters that allow the FIFO to properly recover from data alignment problems caused by FIFO underflow. A pair of counters store read and write pointers, which indicate the addresses of data read from and written into the buffer. Another counter stores a count of data in the buffer. Buffer underflow causes the count to go negative and the read pointer to advance ahead of the write pointer. Data written into the buffer while the total count is negative is not read out of the buffer. This allows alignment of the data to be restored.
Claims26
A method of writing and reading elements into and out of a buffer, comprising the steps of
- keeping track of a number of erroneous reads;
- and
- not reading a corresponding number of elements written into the buffer following the erroneous reads.
A method of writing to and reading from a Video Display FIFO, the method comprising the steps of:
- writing to the FIFO in response to a write pulse;
- incrementing a count in response to the write pulse;
- decrementing the count in response to the read pulse;
- and
- reading from the FIFO in response to a read pulse, except for data written to the buffer when the count is negative.
A video display FIFO, comprising:
- a buffer;
- means for keeping track of a number of erroneous reads from the buffer due to underflow;
- and
- means for reading from the buffer, the reading means not reading a corresponding number of elements written into the buffer following the erroneous reads.
A Display FIFO, comprising:
- a buffer;
- a write pointer for indicating the addresses at which elements are written to the buffer;
- and
- a read pointer for indicating the addresses from which the elements are read out of the buffer;
- the read pointer being allowed to advance past the write pointer when erroneous reads due to buffer underflow occur;
- the elements written into the buffer behind the read pointer not being read out of the buffer.
A digital video system comprising:
- a video retrieval module;
- a display device;
- and
- a Video Display FIFO including a buffer;
- a write pointer for indicating the addresses at which elements are written into the buffer from the video retrieval module;
- and a read pointer for indicating the addresses from which the elements are read out of the buffer to the display device;
- the read pointer being allowed to advance past the write pointer when erroneous reads due to underflow of the buffer occur;
- the elements written into the buffer behind the read pointer not being read out of the buffer.
Dependencies are inferred from the claim text.