Patent EP0359137A2 successfully refreshed from Google Patents.
EP0359137A2
Expired / Lapsed
EP
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Universal asynchronous receiver/transmitter
Assignee: National Semiconductor Corp
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Filing: 1989-09-08
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Granted: —
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Expires: 2009-09-08
Abstract
Abstract Data characters to be transferred from a peripheral device to a central processing unit are serially shifted into the receiver shift register of a universal asynchronous receiver/transmitter (UART). A multiple byte first-in-first-out memory stores a plurality of data characters received by the shift register. The UART checks the status of each data character stored in the FIFO to determine whether it will trigger an exception. A bytes till exception register indicates the number of data characters remaining in the FIFO until an exception is encountered. Then, upon request by the CPU, the UART provides the count of consecutive valid data characters from the top of the FIFO to the first exception, eliminating the need to check status on every transferred byte. Each of the multiple channels of the UART includes an Initialization Register. Setting the appropriate bit Initialization Register of any UART channel allows concurrent writes to the same selected register in each channel's register set. This function reduces initialization time for all of the common parameters that are loaded into each channel's registers. The UART implements a methodology which allows for the processing of any control characters or errors received by the UART during DMA while internal and/or external FIFOs are being used.
Inventors
- 👤 Martin S. Michael
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 16:58
CPC Classifications
G; G06; G06F; G06F13/00; G06F13/38; G06F13/382; G06F13/14; G06F13/20; G06F13/28; G06F13/385
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
75 words
In a data communications device that transfers digital data characters received from a first station to a second station and that includes receiver memory means having storage capacity for a plurality of received data characters, the improvement comprising a counter connected to the receiver memory means for indicating a number of consecutive valid data characters that have been received by the receiver memory means for transfer to the second station before an exception is encountered.
Claim 2
Dependent Claim
75 words
In a data communications device that transfers digital data characters received from a first station to a second station and that includes receiver memory means having storage capacity for a plurality of received data characters, the improvement comprising a counter connected to the receiver memory means for indicating a number of consecutive valid data characters that have been received by the receiver memory means for transfer to the second station before an exception is encountered.
Claim 3
Dependent Claim
36 words
A data communications device as in claim 1 and further including means responsive t a read access request from the second station for transferring the number of consecutively received valid data characters to the second station.
Claim 4
Dependent Claim
132 words
A data communications system comprising (a) a first station; (b) a second station that includes means for issuing a read access request; and (c) a data communications device that transfers data characters received from the first station to a second station, the data communications device comprising (i) receiver memory means having a storage capacity for a plurality of data characters received from the first station; (ii) means responsive to the receiver memory means for indicating the number of consecutively received valid data characters remaining in the receiver memory means for transfer to the second station upon receipt of a read access request from the second station; and means responsive to a read access request from the second station for transferring the number of consecutively received valid data characters to the second station.
Claim 5
Dependent Claim
132 words
A data communications system comprising (a) a first station; (b) a second station that includes means for issuing a read access request; and (c) a data communications device that transfers data characters received from the first station to a second station, the data communications device comprising (i) receiver memory means having a storage capacity for a plurality of data characters received from the first station; (ii) means responsive to the receiver memory means for indicating the number of consecutively received valid data characters remaining in the receiver memory means for transfer to the second station upon receipt of a read access request from the second station; and means responsive to a read access request from the second station for transferring the number of consecutively received valid data characters to the second station.
Claim 6
Dependent Claim
129 words
A data communications device that performs serial-to-parallel conversion on digital data characters received from a first station for transfer to a second station, the data communications device comprising (a) a receiver shift register that receives data characters serially transferred from the first station; (b) receiver memory means for storing a plurality of data characters received from the receiver shift register for transfer to the second station; (c) means for identifying whether each data character received by the receiver memory means will trigger an exception; (d) means for indicating a number of consecutive data characters stored in the receiver memory means that are available for transfer to the second station until an exception is triggered; and (e) means for transferring the number of consecutive data characters to the second station.
Claim 7
Dependent Claim
129 words
A data communications device that performs serial-to-parallel conversion on digital data characters received from a first station for transfer to a second station, the data communications device comprising (a) a receiver shift register that receives data characters serially transferred from the first station; (b) receiver memory means for storing a plurality of data characters received from the receiver shift register for transfer to the second station; (c) means for identifying whether each data character received by the receiver memory means will trigger an exception; (d) means for indicating a number of consecutive data characters stored in the receiver memory means that are available for transfer to the second station until an exception is triggered; and (e) means for transferring the number of consecutive data characters to the second station.
Claim 8
Dependent Claim
46 words
A data communications device as in claim 4 wherein the second station comprises a central processing unit, data storage means associated with the central processing unit, and means for transferring the consecutive valid data characters directly from the data communications device to the data storage means.
Claim 9
Dependent Claim
35 words
A data communications device as in claim 4 wherein the means for identifying includes means for comparing the data characters received from the first station with preselected comparison information stored in the means for comparing.
Claim 10
Dependent Claim
18 words
A data communications device as in claim 6 and further including means for changing the preselected comparison information.
Claim 11
Dependent Claim
28 words
A data communications device as in claim 4 wherein the means for identifying includes means for identifying line status errors in data characters received from the first station.
Claim 12
Dependent Claim
41 words
A data communications device as in claim 4 wherein the means for identifying valid data characters includes means identifying that a data character received by the data communications device is the most recent data character received by the data communications device.
Claim 13
Dependent Claim
78 words
A data communications system comprising: (a) means for storing a plurality of data characters received by a data communications from a first station; (b) means for determining whether each received data character will trigger an exception; (c) means for maintaining a count of the number of consecutive stored data characters that can be transferred to a second station before an exception is encountered; (d) means for transferring the number of consecutive stored data characters to the second station.
Claim 14
Dependent Claim
78 words
A data communications system comprising: (a) means for storing a plurality of data characters received by a data communications from a first station; (b) means for determining whether each received data character will trigger an exception; (c) means for maintaining a count of the number of consecutive stored data characters that can be transferred to a second station before an exception is encountered; (d) means for transferring the number of consecutive stored data characters to the second station.
Claim 15
Independent Claim
101 words
A method of reading a plurality of data characters from a data communications device that receives data character from a first station and transfers the received data characters to a second station, the method comprising: (a) storing a plurality of data characters received by the data communications device from the first station; (b) determining whether each received data character will trigger an exception; (c) maintaining a count of the number of consecutive stored data characters that can be transferred to the second station before an exception is encountered; (d) transforming the number of consecutive valid data characters to the second station.
Claim 16
Independent Claim
101 words
A method of reading a plurality of data characters from a data communications device that receives data character from a first station and transfers the received data characters to a second station, the method comprising: (a) storing a plurality of data characters received by the data communications device from the first station; (b) determining whether each received data character will trigger an exception; (c) maintaining a count of the number of consecutive stored data characters that can be transferred to the second station before an exception is encountered; (d) transforming the number of consecutive valid data characters to the second station.
Claim 17
Dependent Claim
40 words
A method as in claim 11 wherein the second station comprises a central processing unit, storage means associated with the central processing unit, the method includes the step of transferring the consecutive valid data characters directly to the storage means.
Claim 18
Dependent Claim
64 words
A method as in claim 11 wherein the step of determining whether each received data character will trigger an exception includes the step of comparing each received data character with preselected comparison information such that a match between the received data character and the preselected comparison information results in that data character have been determined as a data character that will trigger an exception.
Claim 19
Dependent Claim
13 words
A method as in claim 1 step of changing the preselected comparison information.
Claim 20
Dependent Claim
52 words
A method as in claim 11 wherein the step of determining whether reach received data character will trigger an exception includes the step of determining whether a received data character includes a-line status error wherein transfer to the second station of a data character including a line status will trigger an exception.
Claim 21
Dependent Claim
54 words
A method as in claim 11 wherein the step of determining whether each received data character will trigger an exception includes the step of determining whether a received data character is the most recently stored data character wherein transfer to the second station of the most recently stored data character will trigger an exception.
Claim 22
Dependent Claim
83 words
In a data communications device that includes a plurality of communications channels for transferring data characters between a first system and a plurality of peripheral systems, each of the channels being associated with a corresponding peripheral system for data character transfer between that peripheral system, and the first system, wherein each channel includes an identical register set having for storing digital information the improvement comprising an alternate function selector for enabling concurrent writes to the same selected register in each channel's register set.
Claim 23
Dependent Claim
83 words
In a data communications device that includes a plurality of communications channels for transferring data characters between a first system and a plurality of peripheral systems, each of the channels being associated with a corresponding peripheral system for data character transfer between that peripheral system, and the first system, wherein each channel includes an identical register set having for storing digital information the improvement comprising an alternate function selector for enabling concurrent writes to the same selected register in each channel's register set.
Claim 24
Dependent Claim
110 words
A data communications device that transfers data characters between a plurality of peripheral stations and a common central station, the data communications device comprising (a) a plurality of communications channels, each channel being associated with a corresponding one of the peripheral stations for data character transfer between that peripheral station and the central station, each channel including an identical register set that includes at least one register for storing digital information relating to the data character transfers; (b) means for loading digital information into the register sets; and (c) means connected to each of the channels for enabling concurrent writes to the same selected register in each channel's register set.
Claim 25
Dependent Claim
110 words
A data communications device that transfers data characters between a plurality of peripheral stations and a common central station, the data communications device comprising (a) a plurality of communications channels, each channel being associated with a corresponding one of the peripheral stations for data character transfer between that peripheral station and the central station, each channel including an identical register set that includes at least one register for storing digital information relating to the data character transfers; (b) means for loading digital information into the register sets; and (c) means connected to each of the channels for enabling concurrent writes to the same selected register in each channel's register set.
Claim 26
Dependent Claim
53 words
A data communications device as in claim 18 wherein the means for enabling comprises an alternate function register in each of the channel's register sets, each alternate function register including a bit which if enabled in any alternate function register enables concurrent writes to the same selected register in each channel's register set.
Claim 27
Independent Claim
141 words
A method of transferring data characters from the system memory of a data processing system having a direct memory access unit associated therewith to a data communications device utilizing the direct memory access unit, the data communications device including transmitter memory means having storage locations for a plurality of data characters received by the data communications device from the system memory, the method comprising: (a) determining whether the transmitter memory means is empty; (b) establishing a count of the number of data characters that are to be transferred from the system memory to the data communications device; (c) enabling the direct memory access unit for direct transfer of the number of data characters from the system memory to the data communications device; and (d) transferring the number of data characters to the data communications device utilizing the direct memory access unit.
Claim 28
Independent Claim
141 words
A method of transferring data characters from the system memory of a data processing system having a direct memory access unit associated therewith to a data communications device utilizing the direct memory access unit, the data communications device including transmitter memory means having storage locations for a plurality of data characters received by the data communications device from the system memory, the method comprising: (a) determining whether the transmitter memory means is empty; (b) establishing a count of the number of data characters that are to be transferred from the system memory to the data communications device; (c) enabling the direct memory access unit for direct transfer of the number of data characters from the system memory to the data communications device; and (d) transferring the number of data characters to the data communications device utilizing the direct memory access unit.
Claim 29
Dependent Claim
162 words
A data processing system comprising: (a) a data processing system having a direct memory access unit associated therewith for transferring data characters from the system memory of the data processing system to a data communications device utilizing the direct memory access unit; (b) a data communications device comprising (i) transmitter memory means having storage locations for a plurality of data characters received by the data communications device from the system memory; (ii) means for determining whether the transmitter memory means is empty; (iii) means for establishing a count of the number of data characters that are to be transferred from the system memory to the data communications device utilizing the direct memory access unit; (iv) means for enabling the direct memory access unit for direct transfer of the number of data characters from the system memory to the data communications device; and (v) means for transferring the number of data characters to the data communications device utilizing the direct memory access unit.
Claim 30
Dependent Claim
162 words
A data processing system comprising: (a) a data processing system having a direct memory access unit associated therewith for transferring data characters from the system memory of the data processing system to a data communications device utilizing the direct memory access unit; (b) a data communications device comprising (i) transmitter memory means having storage locations for a plurality of data characters received by the data communications device from the system memory; (ii) means for determining whether the transmitter memory means is empty; (iii) means for establishing a count of the number of data characters that are to be transferred from the system memory to the data communications device utilizing the direct memory access unit; (iv) means for enabling the direct memory access unit for direct transfer of the number of data characters from the system memory to the data communications device; and (v) means for transferring the number of data characters to the data communications device utilizing the direct memory access unit.
Claim 31
Independent Claim
98 words
A method of transferring data characters from the system memory of a data processing system having a direct memory access unit associated therewith to an external storage unit have storage locations for a plurality of data characters, the method comprising: (a) determining whether the external storage unit is empty; (b) establishing a count of the number of data characters that are to be transferred from the system memory to the external storage unit; (c) enabling the direct memory access unit for direct transfer of the number of data characters from the system memory to the external storage unit.
Claim 32
Independent Claim
98 words
A method of transferring data characters from the system memory of a data processing system having a direct memory access unit associated therewith to an external storage unit have storage locations for a plurality of data characters, the method comprising: (a) determining whether the external storage unit is empty; (b) establishing a count of the number of data characters that are to be transferred from the system memory to the external storage unit; (c) enabling the direct memory access unit for direct transfer of the number of data characters from the system memory to the external storage unit.
Claim 33
Dependent Claim
72 words
A method as in claim 23 and further including the steps of issuing an interrupt to the data processing system when the number of data characters have been transferred from the system memory to the external storage unit; identifying the interrupt as indicating that the number of data characters has been transferred to the external storage unit; disabling the interrupt; reenabling the direct memory access unit to facilitate subsequent data character transfers;
Claim 34
Independent Claim
186 words
A method of transferring data characters from a data communications device to the system memory of a data processing system utilizing a direct memory access unit associated with the data processing system, the data communications device including receiver memory means having storage locations for a plurality of data characters received by the data communications device from a peripheral system for transfer to the system memory, the method comprising (a) maintaining a count of the number of data characters available for transfer from the receiver memory means before an exception is encountered; (b) establishing a trigger level for the receiver memory means; (c) initiating the transfer of data characters from the receiver memory means to the system memory utilizing the direct memory access unit when the receiver memory means trigger level is reached; (d) continuing the transfer of data characters from the receiver memory means to the system memory utilizing the direct memory access unit until either an exception is encountered or until the number of valid data characters remaining to be transferred is less than the width of the data bus of the data processing system.
Claim 35
Independent Claim
186 words
A method of transferring data characters from a data communications device to the system memory of a data processing system utilizing a direct memory access unit associated with the data processing system, the data communications device including receiver memory means having storage locations for a plurality of data characters received by the data communications device from a peripheral system for transfer to the system memory, the method comprising (a) maintaining a count of the number of data characters available for transfer from the receiver memory means before an exception is encountered; (b) establishing a trigger level for the receiver memory means; (c) initiating the transfer of data characters from the receiver memory means to the system memory utilizing the direct memory access unit when the receiver memory means trigger level is reached; (d) continuing the transfer of data characters from the receiver memory means to the system memory utilizing the direct memory access unit until either an exception is encountered or until the number of valid data characters remaining to be transferred is less than the width of the data bus of the data processing system.
Claim 36
Dependent Claim
53 words
A method as in claim 25 wherein transfer of data characters continues until an exception is encountered, the exception being an empty receiver memory means, the method including the additional step of terminating all data character transfers from the receiver memory means until the trigger level of the receiver memory means is reached.
Claim 37
Dependent Claim
124 words
A method as in claim 25 wherein transfer of data characters continues until an exception is encountered, the exception being a line status error, the method including the following additional steps: (a) issuing an interrupt to the data processing system; (b) determining the type of interrupt; (c) determining the location of valid data in the receiver memory means; (d) determining the specific nature of the exception; (e) clearing the interrupt; (f) executing a service routine for the specific line status error interrupt; (g) clearing the receiver memory means; (h) executing a purge routine to eliminate the remaining incoming data associated with the data character that triggered the exception; and (i) requesting retransmissions of the data associated with the data character that triggered the exception.
Claim 38
Dependent Claim
102 words
A method as in claim 25 wherein transfer of data characters continues until an exception is encountered, the exception being a match between a data character received by the data communications device and preselected comparison information, the method including the following additional steps: (a) issuing an interrupt to the data processing system; (b) determining the type of interrupt; (c) determining the location of valid data characters in the receiver memory means; (d) identifying the matched data character; (e) reaching the first storage location in the receiver memory means, discarding the matched data character; and (f) executing an appropriate control character service routine.
Claim 39
Dependent Claim
58 words
A method as in claim 25 wherein transfer of data characters continues until the number of data characters remaining to be transferred is less than the width of the data bus, the method including the additional step of terminating transfers from the receiver memory means utilizing the direct memory access unit until the trigger level has been reached.
Claim 40
Dependent Claim
114 words
A method as in claim 25 wherein transfer of data characters continues until the number of data characters remaining to be transferred is less that the width of the data bus and data character transfers have been discontinued for a preselected timeout period, the method including the following additional steps: (a) issuing an interrupt to the data processing system; (b) identifying the interrupt and the number of valid data characters remaining to be transferred; (c) transferring the number of consecutive valid data characters remaining to be transferred; (d) enabling the direct memory access unit for subsequent data character transfers from the receiver memory means to the system memory utilizing the direct memory access unit.
Claim 41
Dependent Claim
197 words
A data processing system for transferring data characters from a data communications device to the system memory of a data processing system utilizing a direct memory access unit associated with the data processing system, the data communication device including receiver memory means having storage locations for a plurality of data characters received by the data communications device from a peripheral system for transfer to the system memory, the data processing system comprising: (a) means for maintaining account of the number of data characters available for transfer from the receiver memory means before an exception is encountered; (b) means for establishing a trigger level for the receiver memory means; (c) means for initiating the transfer data characters from the receiver memory means to the system memory utilizing the direct memory access unit when the receiver memory means trigger level is reached; and (d) means for continuing the transfer of data characters from the receiver memory means to the system memory utilizing the direct memory access unit until either an exception is encountered or until the number of valid data characters remain to be transferred is less than the with of the data bus of the data processing system.
Claim 42
Dependent Claim
197 words
A data processing system for transferring data characters from a data communications device to the system memory of a data processing system utilizing a direct memory access unit associated with the data processing system, the data communication device including receiver memory means having storage locations for a plurality of data characters received by the data communications device from a peripheral system for transfer to the system memory, the data processing system comprising: (a) means for maintaining account of the number of data characters available for transfer from the receiver memory means before an exception is encountered; (b) means for establishing a trigger level for the receiver memory means; (c) means for initiating the transfer data characters from the receiver memory means to the system memory utilizing the direct memory access unit when the receiver memory means trigger level is reached; and (d) means for continuing the transfer of data characters from the receiver memory means to the system memory utilizing the direct memory access unit until either an exception is encountered or until the number of valid data characters remain to be transferred is less than the with of the data bus of the data processing system.
Claim 43
Independent Claim
218 words
A method of transferring data character from a data communications device to an external storage unit for transfer to the system memory of a data processing system utilizing the direct memory access unit associated with the data processing system the external storage unit having storage locations for a plurality of data characters received from the data communications device the data communications device having storage locations for a plurality of data characters received by the data communications device from a peripheral system, the method comprising: (a) establishing a preselected number of data characters that may be transferred from the receiver memory means to the external storage unit utilizing the direct memory access unit; (b) establishing a trigger level for the receiver memory means; (c) initiating the transfer of data characters from the receiver memory means to the external storage unit utilizing the direct memory access unit when the receiver memory means trigger level is reached; continuing the transfer of data characters from the receiver memory means to the external storage unit utilizing the direct memory access unit until either the preselected number of data character has been transferred, or an exception is encountered or until the number of valid data characters remaining to be transferred is less than the width of the data bus of the data processing system.
Claim 44
Independent Claim
218 words
A method of transferring data character from a data communications device to an external storage unit for transfer to the system memory of a data processing system utilizing the direct memory access unit associated with the data processing system the external storage unit having storage locations for a plurality of data characters received from the data communications device the data communications device having storage locations for a plurality of data characters received by the data communications device from a peripheral system, the method comprising: (a) establishing a preselected number of data characters that may be transferred from the receiver memory means to the external storage unit utilizing the direct memory access unit; (b) establishing a trigger level for the receiver memory means; (c) initiating the transfer of data characters from the receiver memory means to the external storage unit utilizing the direct memory access unit when the receiver memory means trigger level is reached; continuing the transfer of data characters from the receiver memory means to the external storage unit utilizing the direct memory access unit until either the preselected number of data character has been transferred, or an exception is encountered or until the number of valid data characters remaining to be transferred is less than the width of the data bus of the data processing system.
Claim 45
Dependent Claim
84 words
A method as in claim 32 wherein transfer of data characters continues until the receiver memory means trigger level is reached, the method including the additional steps of (a) issuing an interrupt to the data processing system; (b) reading the number of characters that have been transferred to the external storage unit; (c) clearing the interrupt; (d) processing the data characters stored in the external storage unit; (e) enabling the direct memory access unit for subsequent data character transfers from the receiver memory means.
References Cited (Backward Citations)
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