CN102799537B - Management method for dual-port RAM (Random Access Memory) buffer in spacecraft AOS (Advanced Orbiting System) - Google Patents

Abstract

The invention discloses a management method for a dual-port RAM (Random Access Memory) buffer in a spacecraft AOS (Advanced Orbiting System). The management method comprises the following steps of: partitioning the dual-port RAM buffer according to the length of VCDU (Virtual Channel Data Unit) data packets in the AOS, and coding partitioned sub-partitions; when the VCDU data packet is written, determining the to-be-written sub-partition according to a writing selection signal, wherein if the sub-partition is empty, the VCDU data packet is written into the sub-partition and the writing selection signal points to the next sub-partition, and if the sub-partition is full, the VCDU data packet is discarded; and when the VCDU data packet is read, determining the to-be-read sub-partition according to a reading selection signal, wherein if the sub-partition is full, the VCDU data packet in the sub-partition is read, and the reading selection signal points to the next to-be-read sub-partition, and if the sub-partition is empty, abandoning the current reading operation. The method disclosed by the invention realizes independent storage management on the VCDU data packets in the dual-port RAM buffer.

Description

A kind of spacecraft AOS system dual port RAM buffer management method

Technical field

The present invention relates to a kind of spacecraft AOS system dual port RAM buffer management method.

Background technology

Data service and the data type of the spacecrafts such as novel remote sensing satellite, deep space probe and airship are numerous, the attribute such as speed, distribution, real-time, importance, transmission quality requirements of Various types of data is different, therefore generally adopt dirigibility is strong, adaptability is good AOS (AdvancedOrbiting System, Advanced Orbiting Systems) agreement to carry out the packaging of data, scheduling and multiple connection process when Aerospace Data Systems designs.According to AOS agreement, the data of various particular type are after packaging and format process, several virtual channel data unit unit (the Virtual Channel Data Unit that length is fixed, form is identical is formed by data category, VCDU), corresponding pseudo channel (the Virtual Channel of every class VCDU, VC), each pseudo channel with the transmission cycle of VCDU frame for time slot time-sharing multiplex Same Physical channel, by scheduling multiple connection realize all VCDU data cells on the physical channel alternately, transmit continuously.

The AOS protocol processes equipment (as data multiplexer) of spacecraft is in the process of VCDU scheduling service data and multiple connection process, be required to be each virtual channel allocation and organize suitable buffer area for receiving VCDU data cell, this buffer area should at wider speed range endoadaptation synchronous, asynchronous or etc. time input, can export when physical channel provide and wait at a high speed again simultaneously.Under the condition that Storage and Processing resource is all limited on star, need that a kind of interface operation is simple, zmodem, high efficiency buffer zone tissue and management method, realize the high speed scheduling of VCDU Service Data Unit and transmit.

Because VCDU service needed exports high-speed data-flow, therefore in AOS protocol processes equipment, adopt the internal logic resource of high speed fpga chip and buffer memory area resource to realize VCDU business function.In the prior art, buffer area is usually designed to FIFO form, and the operation of its read-write interface is comparatively simple, but have under space radiation environment impact, there is data shifts and logic upset after the inherent shortcoming that cannot independently recover.Adopt the design of double-interface RAM buffer district can overcome the defect of FIFO well, but existing scheme needs line module participate in the address administration in double-interface RAM buffer district and switch control usually, make design complicated, reliability reduces, and well can not adapt to the application requirement of spacecraft data system.

Summary of the invention

Technology of the present invention is dealt with problems and is: for the deficiencies in the prior art, provides a kind of spacecraft AOS system dual port RAM buffer management method, achieves the autonomic storage management of VCDU packet in dual port RAM buffer zone.

Technical solution of the present invention is:

A kind of spacecraft AOS system dual port RAM buffer management method, for reading and writing from main control to dual port RAM, comprises the following steps:

According to the length of VCDU packet in AOS system, dual port RAM buffer zone is divided, and the child partition after dividing is encoded;

During write VCDU packet:

Receive the VCDU data stream of input; Signal is selected to determine child partition to be written according to write;

If child partition is dummy status, then by VCDU packet write child partition, and signal is selected to point to next child partition write at the end of write; If child partition is full state, then by VCDU data packet discarding;

When reading VCDU packet:

Signal is selected to determine child partition to be read according to reading;

If child partition is full state, then the VCDU packet in child partition is read, and select signal to point to the next child partition continued by reading at the end of reading; If child partition is dummy status, then abandon current read operation.

Further, when writing VCDU packet, each VCDU packet is all according to the writing address scope write dual port RAM of 0 ~ L-1, and said write selects signal to determine current write child partition; When the writing address writing VCDU packet is L, said write selects signal to point to next child partition, and the current child partition of juxtaposition is full, and wherein, L is described VCDU data packet length.

Further, when reading VCDU packet, each VCDU packet all reads dual port RAM according to the reading address realm of 0 ~ L-1, and described reading selects signal to determine current reading child partition; When the reading address reading VCDU packet is L, described reading selects signal to point to next child partition, and the current child partition of juxtaposition is empty, and wherein, L is described VCDU data packet length.

Further, described child partition has sky marking signal and full marking signal, when described empty marking signal effectively and full scale will invalidating signal then corresponding child partition be dummy status, when described full marking signal is effective and the invalid then corresponding child partition of empty marking signal is full state, described empty marking signal drives by reading clock, and full marking signal drives by writing clock; After child partition writes complete VCDU packet, writing clock, to put full marking signal be effective, and after reading clock detection to effective full scale will, it is invalid for putting sky marking signal; After child partition reads complete VCDU packet, read clock and put sky marking signal effectively, after writing clock detection to effective empty marking signal, it is invalid for putting full marking signal.

The present invention compared with prior art tool has the following advantages:

(1) adopt the buffer zone external interface simple general-purpose of dual port RAM buffer zone autonomous management method, there is the advantage identical with fifo buffer, be convenient to adopt in the design of spacecraft AOS protocol devices; Tissue and the switching of inside, buffer zone adopt the autonomous control mode of closed loop, externally transparent, participate in, save on-board processing resource, reduce system design complexity without the need to line module.

(2) compared with the fifo buffer adopted in prior art, dual port RAM buffer zone has better fault freedom in space radiation environment.When there are single-particle inversion or bursty interference data, FIFO can occurrence logic mistake and internal data displacement fault persistent accumulation and cannot recovering, and ground receiving equipment must carry out complicated fault-tolerant processing to data.Can recover voluntarily after ram buffer generation single-particle inversion in the present invention, bursty interference data can be dropped and there will not be data shifts mistake, reduce the processing load of ground receiving system.

(3) by judging the sky of dual port RAM child partition, the feasibility of full scale will two signal determination data read-write operations, achieve one and read and write authorization reliably, abandon newly arrived data when all child partitions are all not empty, can the data in buffer zone be protected; When all child partitions all less than time abandon read operation, can effectively prevent interfering data in short-term to export.

Accompanying drawing explanation

Fig. 1 is process flow diagram of the present invention;

Fig. 2 is write timing relation;

Fig. 3 is readout sequence relation.

Embodiment

Just flow process shown in 1 is described further the present invention by reference to the accompanying drawings below.

To be operating as example to VCDU data cell in AOS system, it is k that AOS system arranges pseudo channel quantity altogether, pseudo channel multiple connection output code speed is greater than the input code velocity maximum sum of pseudo channel, and the VCDU data cell that namely each pseudo channel receives can be read by multiple connection scheduler module in time.The length of each pseudo channel VCDU data cell is fixed as L (124Byte≤L≤1275Byte).

(1) according to the length L of above-mentioned VCDU data cell, the buffer zone of each pseudo channel is divided into the child partition of several formed objects, the corresponding one piece of dual port RAM storage area of each child partition.The available buffer size of the i-th road pseudo channel is M _i(Byte), child partition quantity n _ifor:

$n_i=\frac{M_i}{L}{2}^j$

In above formula, i=1 ..., k, k are pseudo channel number; J is integer, n _ifor rounding result.

Determine that the child partition of size is encoded to above-mentioned, adopt binary counting value to encode to each subregion, be designated as: 0b, 1b, 10b, 11b, 100b ..., (2 ^j-1) b.

(2) VCDU packet is write

During write VCDU packet, serial to parallel conversion is carried out to the VCDU data packet stream of serial input and obtains complete single VCDU packet.Outside each write dual port RAM be a complete VCDU packet, namely a VCDU packet writes a full dual port RAM child partition.Each child partition arranges an an empty marking signal EMP and full marking signal FULL, and when to child partition write VCDU packet, operate by byte, for write operation, the writing address scope of each VCDU packet is 0 ~ L-1.Actual storage region in dual port RAM selects signal to determine by the write for each VCDU, and write selects signal to point to the child partition of the VCDU packet storing current write.The write length of the VCDU packet of write is added up, after L byte has write, a complete VCDU packet is written in the child partition selecting signal to specify by write, put current buffer for full state, namely empty marking signal EMP is invalid and full marking signal FULL is effective, and write simultaneously selects signal to add 1 sensing child partition next to be written.

Before write operation is carried out in child partition, the full state of the sky of child partition is needed to check.The empty marking signal EMP and the full marking signal FULL that are utilized as the setting of each child partition judge.If empty marking signal EMP is effectively, full marking signal FULL is invalid, then current child partition is empty, allows write VCDU packet; Otherwise current child partition is full, shows that all child partitions have been write full, there is not the child partition being in dummy status, then abandon the current VCDU packet needing write.

(3) VCDU packet is read

When reading VCDU packet, the data in dual port RAM buffer zone read a complete VCDU packet by multiple connection scheduling unit by byte at every turn, namely read the child partition of an empty storage VCDU packet.Corresponding with write VCDU packet, for read operation, the reading effective range of multiple connection scheduling unit is 0 ~ L-1, and the VCDU packet that concrete data content is stored by the child partition read in the dual port RAM selecting signal sensing is determined.

Before child partition is read, the same empty marking signal EMP and full marking signal FULL that adopts carries out the judgement of empty full state to child partition to be read.If child partition non-NULL, then by pressing address realm 0 ~ L-1, data are wherein read as a complete VCDU packet; Otherwise, there is not the child partition being in full state, abandon current read operation.

In above-mentioned write or read operation process, the interface signal relevant to dual port RAM comprises:

Write operation comprises: write clock CLKw; Write enable WrEN, effective when data write; Write address WrAddr, incremental count after every byte data write, scope is 0 ~ L-1; The direct control data of above signal is by byte write dual port RAM.

Read operation comprises: read clock CLKr; Read enable RdEN, effective length is L byte; Read address RdAddr, incremental count after every byte data reads, scope is 0 ~ L-1; Above signal is directly used in control dual port RAM and exports data by byte.

Corresponding to above-mentioned interface signal, in write or readout, EMP signal drives by reading clock CLKr, changes at CLKr rising edge, put this child partition of 1 expression to be read out for empty or data, set to 0 in this child partition of expression and be written into a VCDU packet and do not read.FULL signal drives by writing clock CLKw, in the change of CLKw rising edge, puts in this subregion of 1 expression and has been written with a frame data wait reading, sets to 0 and represents that this subregion is that empty permission writes data.The EMP of each subregion of original state is masked as 1, FULL and is masked as 0.

The operation condition of empty full Status Flag signal is as follows:

EMP puts 1 condition: read address RdAddr and arrive VCDU frame end, RdAddr=L;

EMP sets to 0 condition: by CLKr sampling FULL signal, be 0 when detecting that FULL rising edge puts EMP;

FULL puts 1 condition: write address WrAddr arrives VCDU frame end, WrAddr=L;

FULL sets to 0 condition: by CLKw sampling EMP signal, be 0 when detecting that EMP rising edge puts FULL.

Above child partition empty full scale will synchronization mechanism is embodied in the autonomous management of dual port RAM buffer zone, and writes the circulation selection selected signal Wr_Sel and read to select signal Rd_Sel child partition.According to RAM division result, Wr_Sel signal and Rd_Sel signal that width is j bit are set, are respectively used to control write operation and read operation and switch between each child partition.The child partition numbering of the corresponding current selected of binary counting value of Wr_Sel signal and Rd_Sel signal, initial value is 0b, point to the subregion being numbered 0b, write or read often switches once afterwards, Wr_Sel or Rd_Sel counting adds 1, point to next son subregion, circulate between each child partition according to this, form Lun Zhuan working mechanism.

Wr_Sel signal and Rd_Sel signal-count condition as follows:

Wr_Sel+1: write address WrAddr arrives VCDU frame end, WrAddr=L, and represent that current child partition writes, write operation is switched to next son subregion, and Wr_Sel adds 1 operation and drives by writing clock CLKw;

Rd_Sel+1: read address RdAddr and arrive VCDU frame end, RdAddr=L, represent that current child partition runs through, read operation is switched to next son subregion, and Rd_Sel adds 1 operation and drives by reading clock CLKr.

Embodiment

The embodiment of the present invention can adopt FPGA to realize in the data multiplexing controlling equipment of satellite or airship, and dual port RAM chip and DLC (digital logic circuit) also can be adopted to realize.

Adopt the satellite data system of AOS agreement that 2 pseudo channels are set, VCDU data packet length L is 1020Byte, 1st pseudo channel can be 4096Byte with the capacity of dual port RAM buffer zone, and the 2nd pseudo channel can be 2048Byte with the capacity of dual port RAM buffer zone.

According to VCDU data packet length, child partition division is carried out to dual port RAM buffer zone

Decile is carried out according to VCDU long data packet in dual port RAM buffer zone, and each partition size gets 1024Byte.Pseudo channel 1 available partition number is 4, is numbered 00b, 01b, 10b, 11b, and pseudo channel 2 available partition is 2, is numbered 0b, 1b.

Write interface parameters

Pseudo channel 1: effective width is the gate-control signal Gate1 of 1020 bytes; Serial date transfer DATAw1; Write clock CLKw1 frequency 20MHz, average code speed 10Mbps.Pseudo channel 2: effective width is the gate-control signal Gate2 of 1020 bytes; Serial date transfer DATAw2; Write clock CLKw2 frequency 10MHz, average code speed 1.5Mbps.As shown in Figure 2, buffer zone of the present invention byte-oriented operation, carries out serioparallel exchange to the serial data stream of input in Fig. 2 to write timing relation, and produces and write enable WrEN and write address WrAddr, and writes the direct control signal as dual port RAM together with clock CLKw.

Read interface parameters

Effective length be 1020 bytes read enable RdEN; Reading clock CLKr frequency is 2.5MHz, average code speed 18Mbps; Read address RdAddr, effective model is 0 ~ 1019.Readout sequence relation such as Fig. 3, DATAr are the data that buffer zone exports by byte.

The full marking signal of pseudo channel each child partition sky controls

Pseudo channel 1 is set: empty mark EMP1 [0..3], full scale will FULL1 [0..3]; Pseudo channel 2: empty mark EMP2 [0..1], full scale will FULL2 [0..1].The corresponding relation of empty full scale will and each pseudo channel RAM subregion is as following table 1.

Table 1

Sky mark and the full marking signal of each child partition are arranged in the read-write process of child partition according to above-mentioned interface signal, and the child partition empty full scale will control mode signal that pseudo channel 1 is numbered 00b is as follows:

EMP ₁[0] signal drives by reading clock CLKr, in the change of CLKr rising edge, puts 1 expression 00b subregion and has been read out for empty or data, sets to 0 in expression 00b subregion and has been written into frame data and has not read.FULL ₁[0] signal drives by writing clock CLKw1, in the change of CLKw1 rising edge, puts in 1 expression 00b subregion and has been written with a frame data wait reading, sets to 0 and represents that 00b subregion is that empty permission writes data.The EMP of original state 00b subregion ₁[0] 1, FULL is masked as ₁[0] 0 is masked as.The condition of marking signal action is as follows:

EMP ₁[0] 1 condition is put: read address RdAddr and arrive VCDU frame end, RdAddr=1020;

EMP ₁[0] condition is set to 0: to be sampled FULL by CLKr ₁[0] signal, when FULL being detected ₁[0] rising edge puts EMP ₁[0] be 0;

FULL ₁[0] 1 condition is put: write address WrAddr1 arrives VCDU frame end, WrAddr1=1020;

FULL ₁[0] condition is set to 0: to be sampled EMP by CLKw1 ₁[0] signal, when EMP being detected ₁[0] rising edge puts FULL ₁[0] be 0.

The control mode of empty, the full marking signal of other child partitions is identical with above-mentioned 00b subregion.

Child partition switch-over control signal is set

Pseudo channel 1: write and select Wr_ Se, read to select Rd_Sel1, width is 2bit; Pseudo channel 2: write and select Wr_Sel2, read to select Rd_Sel2, width is 1 bit.Read-write selects the corresponding relation of signal and each pseudo channel RAM subregion as following table 2.

Table 2

Wr_Sel1 signal and Rd_Sel1 signal original state are 00b, point to the 00b subregion of pseudo channel 1; Wr_Sel2 signal and Rd_Sel2 signal original state are 0b, point to the 0b subregion of pseudo channel 2.

Writing of pseudo channel 1 is selected Wr_Sel1 signal and reads to select Rd_Sel1 signal switching mode as follows:

Wr_Sel1+1: when write address WrAddr1 arrives VCDU packet end, WrAddr1=1020, represent that current child partition writes, write operation is switched to next son subregion, and Wr_Sel1 adds 1 operation and drives by writing clock CLKw1.

Rd_Sel1+1: read address RdAddr and arrive VCDU packet end, RdAddr=1020, represent that current child partition runs through, read operation is switched to next son subregion, and Rd_Sel1 adds 1 operation and drives by reading clock CLKr.

Write and select Wr_Sel1 signal to change with the mode reading to select Rd_Sel1 signal to count according to binary cyclic, be followed successively by 00b, 01b, 10b, 11b, 00b ..., realize 4 pieces of child partitions that pseudo channel 1 is pointed in circulation like this, reach the target of switching.

Writing of pseudo channel 2 is selected Wr_Sel2 signal and reads to select Rd_Sel2 control mode signal same as described above, according to 1bit cycle count, is followed successively by 0b, 1b, 0b, 1b, 0b ..., realizes blocked operation between 2 pieces of child partitions of pseudo channel 2.

Write authorization control

The buffer data read-write process of pseudo channel 1 and pseudo channel 2 is completely independent.When meeting the Writing condition of child partition, the VCDU packet of outside input can write direct in the current child partition of channel.

The enabled condition of writing of pseudo channel 1 is: write and select Wr_Sel1 to choose current child partition, current child partition sky is masked as 1, is completely masked as 0.Original state Wr_Sel1 points to 00b subregion, and the sky mark EMP of 00b subregion ₁[0] be 1, full scale will FULL ₁[0] be 0, so allow write data, after having 1 frame VCDU packet write in 00b, Wr_Sel1+1 points to the child partition being numbered 01b, when again there being VCDU packet to arrive, then judge 01b subregion Writing condition, namely write 01b subregion when permitted, write operation is afterwards carried out successively in each by stages.The write authorization control mode of pseudo channel 2 is identical with pseudo channel 1.

When there being new VCDU packet to arrive, but write the current bay non-NULL selecting signal to choose, namely sky is masked as 0 or be completely masked as 1, then newly arrived VCDU data are dropped.

When some VCDU packets, in current child partition ablation process, the imperfect mistake of length occur, then read-write selects the operation condition of the empty full scale will of signal and child partition not meet, the state of a control of current RAM subregion remains unchanged, still can write current RAM subregion when again having new VCDU data to arrive, cover the deficiency of data of last time.

Read authority controls

The enabled condition of reading of pseudo channel 1 is: read to select Rd_Sel1 to choose current child partition; Current child partition sky is masked as 0, and full scale will FULL is 1, and the transmission enable signal RdEN from multiple connection scheduler module is effective.Initially after having a frame VCDU packet write, first propose read data request by 00b subregion, now read to select Rd_Sel1 to point to 00b subregion, its empty mark EMP ₁[0] be 0, full scale will FULL ₁[0] be 1, when read data request is obtained the authorization, RdEN is effective for transmission enable signal, and meet like this and read enabled condition, multiple connection scheduler module reads frame data from the 00b subregion of pseudo channel 1.Run through rear 00b subregion and become dummy status, Rd_Sel1+1 points to 01b subregion, when 01b subregion proposes sense data when read request is obtained the authorization.2 block RAM partition datas reading control procedures of pseudo channel 2 are identical with pseudo channel 1.

The reading of any one RAM subregion completes or writes completion status and all can trigger corresponding empty mark, full scale will, write and select or read to select signal automatic switchover wheel to turn.

According to above implementation procedure, adopt FPGA to design easily, FPGA design proposal of the present invention has been applied in certain remote sensing satellite data multiplexing device, and operation on orbit is good.

The unspecified part of the present invention belongs to general knowledge as well known to those skilled in the art.

Claims (4)

1. a spacecraft AOS system dual port RAM buffer management method, for reading and writing from main control to dual port RAM, tissue and the switching of inside, buffer zone adopt the autonomous control mode of closed loop, externally transparent, participate in without the need to line module, ram buffer can independently recover after generation single-particle inversion mistake, it is characterized in that comprising the following steps:

According to the length L of VCDU packet in AOS system, dual port RAM buffer zone is divided, and to the child partition coding after dividing, adopts binary counting value to encode to each subregion, be designated as: 0b, 1b, 10b, 11b, 100b ..., (2 ^j-1) b;

According to RAM division result, setting is write and is selected signal and read to select signal, be respectively used to control write operation and read operation switch between each child partition, write the child partition coding selected signal and read to select the corresponding current selected of the binary counting value of signal, time initial, be 0b, point to the subregion being numbered 0b, write or read often switches once afterwards, writes and selects signal or read to select signal-count to add 1, point to next son subregion, circulate between each child partition according to this, form deadlock-free Lun Zhuan working mechanism;

Each child partition arranges sky marking signal and full marking signal, interlocking synchronization mechanism is set up between sky mark and full marking signal, mutual monitoring, empty marking signal drives by reading clock, put this child partition of 1 expression for empty, set to 0 and represent that this child partition is full, full marking signal drives by writing clock, it is full for putting this subregion of 1 expression, sets to 0 and represents that this subregion is for empty;

During write VCDU packet:

Determine that write operation control signal comprises: write clock, write enable and write address, write clock, write enable when data write effectively, write address is incremental count after every byte data write, and the direct control data of above signal is by byte write dual port RAM;

Receive the VCDU data stream of input; Signal is selected to determine child partition to be written according to write; The full state of sky of child partition checks;

If child partition is dummy status, then by VCDU packet write child partition, and signal is selected to point to next child partition write at the end of write; If child partition is full state, then by VCDU data packet discarding;

When reading VCDU packet:

Determine that read operation control signal comprises: read clock, read enable and read address, read clock and read enable effective when data reading, read address incremental count after every byte data reads; Above signal is directly used in control dual port RAM and exports data by byte;

Signal is selected to determine child partition to be read according to reading; The full state of sky of child partition checks;

If child partition is full state, then the VCDU packet in child partition is read, and select signal to point to the next child partition continued by reading at the end of reading; If child partition is dummy status, then abandon current read operation.

2. a kind of spacecraft AOS system dual port RAM buffer management method as claimed in claim 1, it is characterized in that: when writing VCDU packet, each VCDU packet is all according to the writing address scope write dual port RAM of 0 ~ L-1, and said write selects signal to determine current write child partition; When the writing address writing VCDU packet is L, said write selects signal to point to next child partition, and the current child partition of juxtaposition is full, and wherein, L is described VCDU data packet length.

3. a kind of spacecraft AOS system dual port RAM buffer management method as claimed in claim 1, it is characterized in that: when reading VCDU packet, each VCDU packet all reads dual port RAM according to the reading address realm of 0 ~ L-1, and described reading selects signal to determine current reading child partition; When the reading address reading VCDU packet is L, described reading selects signal to point to next child partition, and the current child partition of juxtaposition is empty, and wherein, L is described VCDU data packet length.

4. as a kind of spacecraft AOS system dual port RAM buffer management method as described in arbitrary in claims 1 to 3, it is characterized in that: described child partition has sky marking signal and full marking signal, when described empty marking signal effectively and full scale will invalidating signal then corresponding child partition be dummy status, when described full marking signal is effective and the invalid then corresponding child partition of empty marking signal is full state, described empty marking signal drives by reading clock, and full marking signal drives by writing clock; After child partition writes complete VCDU packet, writing clock, to put full marking signal be effective, and after reading clock detection to effective full scale will, it is invalid for putting sky marking signal; After child partition reads complete VCDU packet, read clock and put sky marking signal effectively, after writing clock detection to effective empty marking signal, it is invalid for putting full marking signal.