JPS6224829B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data transmission system, and more particularly to a data transmission system in which a block of data, which is a handling unit of software, is divided into at least one block and the blocks are transmitted and received in a chain.

With the recent progress in distributed processing in the information processing field, situations in which file transfers and image information are transferred are increasing. In such cases, the length of the data handled by the software is often longer than the length of the data handled by the hardware, so it is necessary to divide the data handled by the software into pieces (divided units are called blocks) and pass them to the hardware. be.

Conventional data transmission systems of this type include a register that increments each time a block is successfully transmitted, and the contents of the register are added to each block to be transmitted as a transmission sequence number before being transmitted. By checking the validity of the reception order of each block based on this transmission order number, normal reception is confirmed, a report to that effect is sent to the software, and an acknowledgment is returned, and the sending side receives this acknowledgment. When this message is received, it is assumed that the transmission was successful and a report to that effect is sent to the software.

In such conventional configurations, there is no way to display whether a block corresponds to a start block, intermediate block, or end block of data, so once normal transmission/reception is confirmed, the block is This has the disadvantage that the software must be notified of this, which increases the number of interruptions to the software.

An object of the present invention is to provide a data transmission system that reduces the number of interruptions to software.

The system of the present invention is a data transmission system in which a block of data, which is a handling unit of software, is divided into at least one block and the blocks are transmitted and received in a chain. block type adding means for adding a type indication of whether the block is an independent block, a start block, an intermediate block, or an end block; and a block type adding means that increments each time the independent block or the end block is normally transmitted. 1 transmission order holding means; holding a value one larger than the contents of the first transmission order holding means each time the start block is normally transmitted; and incrementing the value each time an intermediate block is normally transmitted; a second transmission order holding means that increments each time the independent block or the end block is normally received; and a first reception order holding means that increments each time the independent block or the end block is normally received; a second reception order holding means that holds a value one larger than the content of the order holding means and increments each time the intermediate block or the end block is normally received; and the first transmission according to the type indication. and comparison means for comparing the transmission order number in which the content of the order holding means or the second transmission order holding means is set with the first reception order holding means or the second reception order holding means according to the type display. The present invention is characterized in that the normal transmission/reception is reported to the software only at the independent block or the end block.

Next, the present invention will be explained in detail with reference to the drawings.

Referring to FIG. 1, this embodiment includes a transmission buffer 1, a flag circuit 2, an address circuit 3, a control bit circuit 4, a first transmission register 5, a second transmission register 6, a selector 7, a transmission control circuit 8, and a line 9. , a reception buffer 11, a comparator 12, a gate 13, a reception control circuit 14, a first reception register 15, and a second reception register 16.

Data to be sent is from memory (not shown)
The data is divided into 4KB units and transferred to the transmission buffer 1 to form the information part of the block. In the block,
A flag sequence section for indicating the start and end of a block using a fixed bit sequence, an address section for indicating the destination address, and a control section are added by a flag circuit 2, an address circuit 3, and a control bit circuit 4, respectively.

The control section consists of bits that display the block type and transmission order number. The type of block is whether the length of the data input to transmission buffer 1 is 4 KB or less and can be configured as one block (independent block), or it is longer than 4 KB and can be configured as multiple chained blocks (chained blocks). This indicates whether a block corresponds to a start block, an intermediate block, or an end block in a chain of blocks. The transmission sequence numbers of the independent block and the start block are assigned by the first transmission register 5, and the transmission sequence numbers of the intermediate block and the end block are assigned by the second transmission register 6, respectively.

The bits of each block are serialized by the selector 7 in the order of the flag sequence section, address section, control section, information section, and flag sequence section, and are transmitted via the line 9, but the transmission control circuit 8 constitutes the block. A test bit pattern is generated from the bits of each of these parts, and this is often added to a block as a block test sequence part and transmitted.

Blocks sent via line 9 are received at the data station designated by the address field. In order to avoid complicating the drawing, Figure 1 shows only one data station on the transmitting side and one data station on the receiving side, but in reality, a line is connected between one master station and multiple slave stations. connected to enable data transmission.

The information part of the received block is gate 1.
3, the reception buffer 11, the transmission order number is determined by the comparator 12, the flag sequence section, the block type and the block inspection sequence section are determined by the reception control circuit 14.
The information is distributed and input to each. The transmission order number input to the comparator 12 is compared with the contents of the first reception register 15 or the second reception register 16 controlled by the reception control circuit 14 to confirm whether the transmission order number is normal or not (reception confirmation). In response to the result, the block input to receive buffer 11 is transferred bit-by-bit to memory. Also,
The result of the normal reception confirmation is sent back from the reception control circuit 14 to the transmission control circuit 8 as a response signal. Note that the first transmitting register 5 and the first receiving register 15
The contents of are initialized to the same value at the start of data transmission.

2A and 2B are flowcharts mainly for explaining the operation of assigning a transmission sequence number in the transmission control circuit 8, and FIG. 3 is a flowchart mainly for explaining the normal reception confirmation operation in the reception control circuit 14.

First, in FIG. 2A, it is checked in a step (hereinafter referred to as K) whether the data to be transmitted has a length within 4 KB, which is a block unit. Within 4KB,
In other words, if it is an independent block, bits B and E for indicating the block type are set to "1", and the content S2 of the first transmission register 5 is set as the transmission order number N(S) (Ki), and all transmissions are performed. Data transmission takes place. When a positive response is received from the receiving side (K, corresponding to K in Figure 3), that is, a normal reception confirmation response is received in response to the block transmitted from the transmitting buffer 1, the contents of the first transmitting register 5 are changed. S2 is incremented by one (Ke), the software is notified of normal termination (Ko), and the process ends. In K-u, an out-of-order response was received without receiving an acknowledgment (K
(corresponding to Fig. 3), the software is notified of abnormal termination (K) and ends. Also,
In case K does not receive an out-of-order response, retransmission is repeated within the specified number of retries.

In KA, if the transmission data length exceeds 4KB, bit B is set to "1", bit E is set to "0", and the content S2 of the first transmission register 5 is set as the transmission sequence number N(S) (K g), the first divided
4KB (starting block) is sent. Acknowledgment received for this block (K block)
and the number obtained by adding "1" to the content S2 of the first transmission register is the content S3 of the second transmission register (K
i) Check whether the remaining transmission data is still larger than 4KB (Ksa). The operation when no acknowledgment is received in the K unit is the same as in the K unit described above.

When the K server finds that the remaining transmission data is larger than 4KB, it sets bits B and E to "0", that is, indicates an intermediate block, and sets the content S3 of the second transmission register 6 to the transmission order number. N
As (S) (Kshi), 4KB is transmitted. When an acknowledgment is received for this transmission (K), the content S3 of the second transmission register 6 is incremented by one (K
C), it is checked again whether the remaining transmission data is larger than 4 KB (K S), and if it is larger than 4 KB, the above-mentioned operation is repeated. Note that the operation when no acknowledgment is received in K is the same as in the above-mentioned K.

When the K server finds that the remaining transmission data is 4 KB or less, it sets bit B to ``0'' and bit E to ``1,'' indicating that the block is finished, and the contents of the second transmission register 6. S3 is set as the transmission order number N(S) (Kso), and all remaining transmission data is transmitted. When an acknowledgment is received for this transmission (Kta), the contents of the first transmission register 5 S
2 is incremented by one (Ke), the software is notified of normal termination (Ko), and the process ends. The operation when no acknowledgment is received in K-ta is the same as in K-ta described above.

Next, the operation of the reception control circuit 14 will be explained based on FIG. First, in K-chi, it is checked whether the start block received flip-flop (which has been initialized to the reset state) is set. Since it is of course a reset at the beginning, it is checked whether the received block is an independent block or a starting block (K).

When it is found that the block is an independent block or a start block, it is checked whether the transmission order number N(S) of the block matches the content R2 of the first receiving register 15 (K test), and if they match, it is checked. For example, since it was confirmed that the transmission was successful, the first
The number obtained by adding "1" to the content R2 of the receiving register 15 is set as the content R3 of the second receiving register 16, and an acknowledgment is transmitted (Kt). Furthermore, it is checked whether or not the block is an independent block (K), and if it is an independent block, the content R2 of the first receiving register 15 is checked.
Increment the number by one, report the reception to the software (K), and exit. If it is found at K-na that the block is not an independent block, that is, it is a start block, the start block received flip-flop is set (K2) and the process ends.

In addition, in Kte, if the transmission order number N(S) and the content R2 of the first reception register 15 do not match, this transmission order number N(S) is one more than the content R2 of the first reception register 15. Check whether it matches a smaller number (Knu). If they match, it is assumed that there is double reception, that is, the same block has been received twice in a row, and an acknowledgment is sent (K
Ne). This case is limited to cases where independent blocks with the same content are received twice in a row. If there is no match, an out-of-order response is sent (K) and the process ends.

In step K, if it is found that the block is neither an independent block nor a start block, it is checked whether it is an end block (step K). When it is found that it is an end block, the transmission order number N
(S) is 1 from the content R3 of the second reception register 16
Check whether it is equal to the smaller number (Khi). If they are equal, it is assumed that double reception has occurred, an acknowledgment is sent (K), and the process ends; however, this case is limited to cases where the same end block is received twice in a row. If it is found that the block K is not the end block, that is, it is an intermediate block, or that the blocks are not equal in KH, an out-of-order response is sent (K) and the process ends.

In Kchi, it is found that the flip-flop that has received the start block has been set, and as a result of checking whether it is a start block (Kf), it is found that it is a start block, the transmission order number N(S) is determined.
If it is equal to the content R2 of the first reception register 15, an acknowledgment is sent (K) and the process ends. If it is found that the blocks are not equal in K or that they are independent blocks in K, an out-of-order response is sent (K) and the process ends. The fact that K-ho is an independent block means that an independent block is mixed into the chained block.

When it is determined that the block is not an independent block in K-ho, the transmission order number N(S) is stored in the second reception register 16.
is compared with the content R3 (Kma). If they are equal, normal reception has been confirmed, so the content R3 of the second reception register 16 is incremented by one, and an acknowledgment is sent (Kmi). When it is determined that the block in question is the end block (Km), the start block received flip-flop is reset (Km), the content R2 of the first receiving register 15 is incremented by one, and the software Report reception (K
M), end. In the K system, if it is found that the block is not the end block, that is, it is an intermediate block, the block ends immediately. Also, in Kma,
If NO, check whether the transmission order number N(S) is equal to a number one smaller than the content R3 of the second reception register 16 (Kya), and if they are equal, it is assumed that double reception has occurred and an acknowledgment is sent. (K), and if they are not equal, an out-of-order response is sent (K), and the process ends.

Figure 4A represents Figures 2A and 2B explained above.
This is one example of transmission data assumed to more specifically explain the flowcharts in Figures and Figure 3.
FIG. 4B shows the first transmission register 5, second transmission register 6, first reception register 15, second reception register 16, start frame received flip-flop, and transmission order number N( This shows the evolution of S).

In FIG. 4A, transmission data FO is a chain block consisting of a start block 0, intermediate blocks 1 and 2, and an end block 3, transmission data F1 is an independent block, and transmission data F2, F3, and F4 are start blocks 2, 3, and 4, respectively. , end blocks 4, 7, 5, and intermediate blocks 3, 4-6, and the transmitted data are generated in the numerical order shown in FIG. 4A. The software does not recognize, for example, intermediate blocks 1, 2 and end block 3 for the transmitted data FO. Fourth
In diagram B, timing TO indicates the initial state, and timings T1 to T4, T5, T6 to T
8, T9-13, and T14-T15 respectively indicate the states after transmission/reception of transmission data FO, F1, F2, F3, and F4, respectively.

The effect of this embodiment is that, as is clear from the transmission data example shown in FIG. 4A, the transmission sequence number N(S) is a consecutive number in the start block and independent blocks, and in one chain block. Since the start block, intermediate block, and end block are also consecutively numbered, it is possible to switch and manage a single transmission sequence number by software or hardware in response to the block type display. Set the sequence number field to 1
This is something that can be done individually.

In this embodiment, the first transmitting register 5, the second transmitting register 6, the first receiving register 15, and the second
An embodiment in which all the receiving registers 16 are replaced with counters can be easily realized.

As explained above, according to the present invention, instead of interrupting the software and reporting to that effect every time the normal transmission/reception of a block is confirmed,
By adopting the above configuration, it is only necessary to report normal completion to the software when normal transmission/reception is confirmed for the end block of a chain block or an independent block, which reduces the number of software interrupts. can be reduced.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, FIG. 2A,
FIGS. 2B, 3, 4A, and 4B are diagrams for explaining this embodiment. 1... Transmission buffer, 2... Flag circuit, 3...
...Address circuit, 4...Control bit circuit, 5...
First transmission register, 6...Second transmission register, 7
... Selector, 8 ... Transmission control circuit, 9 ... Line, 11 ... Reception buffer, 12 ... Comparator, 1
3...gate, 14...reception control circuit, 15...
1st reception register, 16... 2nd reception register,
Ahhh... step.

Claims (1)

[Scope of Claims] 1. In a data transmission system in which a block of data, which is a handling unit of software, is divided into at least one block and the blocks are transmitted and received in a chain, the block is block type adding means for adding a type indication indicating whether the block is an independent block, a start block, an intermediate block, or an end block; and increments each time the independent block or the end block is normally transmitted. a first transmission order holding means, each time the start block is normally transmitted, a value that is one larger than the content of the first transmission order holding means is stored; a second transmission order holding means that increments each time the independent block or the end block is normally received; and a first reception order holding means that increments each time the independent block or the end block is normally received; a second reception order holding means that holds a value one larger than the content of the reception order holding means and increments each time the intermediate block or the end block is normally received; Comparing means for comparing the transmission order number set with the contents of the transmission order holding means or the second transmission order holding means with the first reception order holding means or the second reception order holding means according to the type display. 3. A data transmission system, characterized in that the normal transmission/reception is reported to software only at the independent block or the termination block.