JPH0292571A - Printer serial interface system - Google Patents

Abstract

PURPOSE:To extend a connection distance between a printer and a computer and to enable an operational assurance as a system by using a high-speed serial interface capable of an error processing. CONSTITUTION:To printer interface PIF, a device IFPS1 and a device IFPS2 respectively having parallel-serial signal conversion circuits PSCH and PSCP are added on the computer side and the printer side by being connected through a serial interface SIF. A set of commands issued from the host computer side are simply parallel/serial converted by the computer-side device IFPS1, thereafter being again serial/parallel converted by the printer-side device IFPS2 to be informed to a printer. On the other hand, various states generated in the printer PRT are parallel/serial converted by the printer-side device IFPS2, thereafter being serial/parallel converted by the computer-side device IFPS1 to be informed to a computer.

Description

[Detailed Description of the Invention] [Summary] Regarding a printer serial interface method when a high-speed serial interface is used as a printer interface to connect a printer and a computer, the present invention provides a high-speed serial interface that can handle errors so that the printer and computer can A printer serial interface method in which a high-speed serial interface is used as a printer interface to connect a printer and a computer, with the aim of extending the connection distance between the printer and the computer and ensuring operation as a system. When an error occurs on the high-speed serial interface, the computer notifies the computer that the printer is powered off without treating the error as an abnormality in the printer, and instructs the printer to reset the printer. , when the error state is recovered after a certain period of time has elapsed after the error detection, the computer is notified that the power of the printer has been turned on again, and the computer resets the status of the printer. Configure.

[Industrial application field]

The present invention relates to a printer serial interface method when a high-speed serial interface is used as a printer interface for connecting a printer and a computer.

In recent years, the field of computers such as personal computers (PCs) has become smaller and lighter.

For example, a laptop computer has the same functions as a desk-top personal computer, is portable, and is space-saving. On the other hand, although some printer devices are small, they are forced to be relatively large due to performance, production cost, and other considerations.

In this case, with a connection method in which the connection distance between the personal computer and the printer is technically limited, even if the main body of the personal computer is a space-saving type, a large printer must be placed on the side, which poses a problem in terms of space. Therefore, attempts have been made to extend the connection distance in order to locate the printer at a remote location, but this will result in various problems as will be described later.

[Problems to be solved by conventional techniques and inventions] Conventionally,
The printer interface connection method between a computer and a printer is generally based on R3-232C or the Centronics interface developed by Centronics Corporation.

For example, the Centronics interface is a parallel interface that uses 8-bit parallel communication between a personal computer and a printer.

However, this method requires an electrical T between these two points.
Since the connection is made by TL, if the connection distance between them is extended, a potential difference will be generated between the two points, causing a problem that the interface cannot operate normally. Therefore, it was necessary to limit the connection distance so as not to generate a potential difference between two points.

Furthermore, the 8-bit parallel interface based on the Centronics interface does not have a means to notify the computer of any error that occurs during the transmission process. Therefore, when using a serial interface, there is a problem in that even if an error occurs and is detected on the serial interface, it cannot be notified to the software.

On the other hand, high-speed and long-distance transmission has become technically possible in communication fields other than printer interfaces. Therefore, it is conceivable to apply the serial interface technology used in the communication field to the printer interface, but simply replacing it with a serial interface would result in a decrease in performance and the need to change the software.

Furthermore, it is practically impossible to guarantee the operation of the system using the above-mentioned protocols in the communication field without changing the existing software. Therefore,
It becomes necessary to develop a serial interface for printers.

An object of the present invention is to extend the connection distance between a personal computer and a printer by using a high-speed serial interface that can handle errors, and to ensure operation as a system.

[Means and effects for solving the problems] The present invention provides a printer serial interface system when a high-speed serial interface is used as a printer interface for connecting a printer and a computer, and the high-speed serial interface When an error occurs on the interface, the computer is notified that the printer is powered off without treating the error as an abnormality in the printer, and the printer is instructed to reset the printer, and after the error is detected, When the printer recovers from the error state after a certain period of time has elapsed, the computer is notified that the power of the printer has been turned on again, and the computer resets the status of the printer. do.

〔Example〕

Conditions to be observed in determining the high-speed serial interface of the present invention include: (1) the software interface is not changed; (2) there is no performance deterioration; (2) operation can be guaranteed as a system; (2) it can be constructed at a low cost.

The present invention defines a printer serial interface protocol that adheres to the above four points.

FIG. 1 is a schematic connection configuration diagram between a host computer and a printer according to the present invention. In the figure, HST is the host computer,
PRT is a printer, PSCH, PSCP are serial-parallel conversion means, D/R, R/D are R5-422 driver/receivers, dν/rν are also driver/receivers, CL
K is a clock generation means. Further, the thin line SIF is a serial interface, and the thick line PIF is a parallel interface.

As shown in the figure, the present invention adds devices IFPSI and IFPS2 having parallel-to-serial signal conversion circuits PSCH and PSCP on the computer side and the printer side, respectively, to the conventional printer interface PIF, and connects them with a serial interface SIF. Connect with. A series of commands issued from the host computer side are simply converted from parallel to serial by the device IFPSI on the computer side, converted again from serial to parallel by the device IFPS2 on the printer side, and notified to the printer.

On the other hand, various states occurring in the printer PRT are subjected to parallel-to-serial conversion by the printer-side device IFPS2, serial-to-parallel conversion by the computer-side device IFPSI, and are notified to the computer.

FIG. 2 is a connection configuration diagram in which the serial-parallel conversion means IFPSI is incorporated into the host computer H5T. The operation of this connection configuration example is almost the same as that shown in FIG. 1, so a description thereof will be omitted.

By the way, as described above, the parallel interface based on the Centronics interface does not have a means to notify the computer of any abnormalities that occur during the transmission process. Therefore, if a serial interface is simply used between these, there is a problem in that even if an error occurs on the serial interface and is detected, it cannot be notified to the software.

The present invention basically solves the above-mentioned conventional problems as follows. That is, when the serial-parallel conversion circuit IFPSI on the computer side detects an error in the received data, it notifies the computer for one second to turn off the power of the printer PRT. During this time, a printer reset is forcibly issued through the transmission data SD. Next, when a received data error is detected on the printer side, a printer reset is issued to notify the computer that the printer is powered off. Through these operations, it appears as if the printer has been restored, and it is possible to make it possible to reprint from the software.

FIGS. 3(a), 3(b), and 3(c) show frame structures of the serial transmission procedure used in the present invention. (a)
, (b) is the frame structure when transferring data from the host side, (c) is the data (control signal) from the printer side
This is the frame structure when transferring.

(a), (b), (In cl, H is on (
1), L is off (0), and the parity bit is odd parity. The bit configuration is 12 bits, and "5tart" (str) corresponds to bit numbers O to 11.
DATA" (DT), "DSTB""5top'
(stp), “parity” (pty) +
Signals such as "extend" (ext) are assigned as shown. Furthermore, the synchronization method is start-stop synchronization.

Next, the functions of these signals will be explained. These signals also include signals compliant with the Centronics interface.

Signal DSTB is a strobe signal for reading data DATAI to DATAB on the printer side. The host side transmits data via the SD signal vA (balanced transmission serial data line sent from the host to the printer as shown in FIG. 1) upon detection of DSTB on. At this time, DATAI~D
Send ATAB at the same time. DSTB off is not detected. On the other hand, when the printer side receives DSTB ON, D
After ATAI to DATA8 are activated to ensure skew (1 μs) and DSTB is turned on for the printer, DSTB is turned off after more than 1 μs has elapsed.

Signals INPRM and EXPRM are signals that bring the printer into an initial state. The host side sends data via the SD signal line upon detection of on/off. The printer side turns on and off the INPRM signal (EXPRM) to the printer in response to reception of on-detection and off-detection data.

Signal ACKNLG is a response and request signal to the DSTB signal. The printer side turns R when 8CKNLG is turned on.
The data is transmitted via line D (balanced serial data line sent from the printer to the host as shown in FIG. 1). A
CKNLG off is not detected. ACKNLG on host side
If it receives an ACKNLG signal, it turns on the ACKNLG signal to the host for 1 μs or more and then turns it off.

The printer side detects whether FAULT is on or off and transmits data through the signal line RD. At this time, RINF1 to RINF3 indicating the status of the printer are also transmitted. After receiving the detection of FAULT ON, the host side changes RINF1 to 3.
After determining , the FAtlLT signal is turned on after 500 nsec or more has elapsed.

Signals BUSY, PE, .5LCTSESIG are all processed in the same way. The printer side sends data via the RD upon detection of on/off. The host side changes each signal line in response to reception of on/off detection data.

There is no skew guarantee for RINF.

Next, error handling in the serial transmission path will be explained.

No error handling is performed on the Centronics interface. The object of error processing according to the present invention is only errors on the serial transmission path. The errors targeted are parity errors, framing errors, and break detection.

In the case of host-side reception data error detection, when a data reception error is detected, the host is notified of printer power off (PON off) for more than Is.

Received data will not be accepted during this printer power off notification. Notifies printer power off until normal data is received after 1 second (S) has elapsed. Furthermore, INP to the printer side
After executing PMNPP and Looms, issue INPRM OFF.

In the case of printer-side reception data error detection, when a data reception error is detected, the TNPPM signal is turned on for 100m5 to the printer. Data received during this time will be cancelled. Data is accepted after the INPPM signal is turned off. Also, data transmission at intervals of 10m5 for 130 minutes is stopped. In addition, the LED lights up when an error is detected on the printer side.

This LED turns off when power is turned on from the outside (reset) or after an error detection is received or when some normal data is received.

Figure 4 is an operation flowchart on the printer side, Figure 5 (al
, (b) is a state transition diagram on the printer side, FIG. 6 is an operation flowchart on the host side, and FIG. 7 (al, (b) is a state transition diagram on the host side.

The operation and state transition on the printer side will be explained with reference to FIGS. 4 and 5. In FIG. 5, (al is the transmission system, (b
) is the receiving system.

In Figure 4, when the printer is powered on from the printer's reset state (1), a 1-second timer is activated and transmission and reception are prohibited (2), and in the transmission process, the 10m5 timer is activated and the signal changes. Monitoring is performed (3), a transmission factor occurs, and data transmission is started (4). On the other hand, in the reception process, the process waits for the received data (5), and if the reception is normal, the signal corresponding to the received data is changed 6), and if the reception is abnormal, the printer reset (INPPM) is issued 7)
, complete the process.

In the transmission system (a) of FIG. 5, the initial state is in the reset state Q (1). The printer is powered on (po
When the 1-second timer is activated, the transmission disable state (2) is entered from the sent state (w, on). In this state, serial-to-parallel conversion on the printer side does not operate. 1 second timer times out (lsec, timeout)
When this happens, it enters the idle state (3). In this state (3
) starts its internal 10ms timer, and when a 10ms timeout (10ms, time out) occurs, it sends the signal status of the printer at that time (Tx),
Transmission complete (Tx end) and idle state (3)
Return to

On the other hand, in (3), before the 10ms timeout occurs, the printer interface signal (*ACKN
LG, *FAULT, BUSY, PH,5LC
When T) changes (ch), the signal state of the printer interface at the time of the change is transmitted from (4) to (3). When the transmission is completed, the device returns to the idle state as described above. At this time, reset the 10ms timer and repeat 1011.
Start a 1 second timer.

The printer is powered off (pow) during each operation.

off), all transition to the reset state.

Nothing is executed in this reset state.

The receiving system fb) in FIG. 5 is initially in the reset state (1), similar to the transmitting system. When the power of the printer is turned on (poh, on), it changes from the reset state to the reception disabled state, and the 1 activated in the transmission system
Reception stops until the second timer times out (2)
. That is, even if data arrives during this reception stop state, the data is ignored.

When a timeout occurs, a transition is made to a state (3) in which reception is possible. When normal data is received in this state, various signals (*DSTB, *INPRM, *EX) are sent to the printer according to the received data (data rev).
PRM, DATAI~DATAB) (4)
. When this control is completed, the next data reception becomes possible.

However, if there is an error in the received data (Rx error), a *
The INPPM signal is controlled to put the printer in the initial state, start a one-second timer, and transition to the unreceivable state. Is timeout of this one second timer
) to transition to a state where it can receive data again.

Figure 6 is an operation flowchart on the host side, Figure 7 is a fat
, (b) is a diagram illustrating state transition on the host side.

FIG. 7(a) shows a transmitting system, and FIG. 7(b) shows a receiving system.

In FIG. 6, from the reset state of the computer (1), the main unit is powered on, enters a waiting state for transmission processing (2), generates a transmission factor, and starts data transmission (3). On the other hand, in reception processing, waiting for received data is 32m.
Activate the 5ec timer 4), turn on the printer power and process various signals for normal reception (5), turn off the printer power for 32m5 timeout 6), prohibit reception and start the IS timer for abnormal reception. Then, the printer power is turned off and an INFRM signal transmission request is made (7).

In the transmission system (al) of FIG. 7, the host side serial-parallel converter is powered on and immediately transitions from the reset state to the idle state g(1).

Here, various printer signals (*DST
B, *INPRM, *EXPRM) and when a change occurs (ch), if the change at that time is a *DSTB signal, it is serialized and transmitted together with DATAI to DATAB (2). Also, *INPRM, *EXP
If it is an RM signal, these states are transmitted. When transmission is completed (trsend), it transitions to an idle state.

If an error occurs in the receiving system while in this idle state (RX 6rror), from (3) * INPRM
Automatically transmits * INPRM signal on/off as the signal changes. When this transmission is completed (4), it transitions to an idle state.

In FIG. 7(b), when the power is turned on and the reset is released, the internal printer power flag is turned off, assuming that the printer is not powered on. Immediately from this state, the device enters the idle state (1) and waits for received data. When normal data is received in this state, the signal state corresponding to the data is set (2) and the device returns to the idle state.

At this time, it is determined that the printer's power is turned on, and the 32m
Starts the second timer and waits for further received data. If the printer is in normal condition, it will send some status information at 10ms intervals, so there is no possibility of a 32ms timeout occurring, but if the printer is turned off or sent from the host side. If the data becomes abnormal on the printer side, the 32 ms timer times out (time out 32 ms) because there is no data sent from the printer side for at least 1 second. Because a timeout occurred, it was assumed that the printer was turned off.3) The printer power flag was turned off and the printer was in an idle state! Transition to IEfil.

Furthermore, when error data (Rx error) is received, the printer changes to a state in which reception is not permitted for one second (4), making it appear to the host that the printer power is turned off.

Furthermore, it notifies the transmission system of the reception error. 1
After seconds have elapsed, it transitions to an idle state and waits for received data.

FIG. 8 +al, (bl, (C1 is an explanatory diagram of the interface signal state.

In the figure, H5T is a host computer, IFPSI is a parallel-to-serial converter on the host side, IFPS2 is a parallel-to-serial converter on the printer side, and PRT is a printer.

Further, the P+5V signal is +5V of the power supply used in the printer device. By checking this power on the computer side, it is possible to determine that the printer is powered on.

(al is the processing of the P +5V signal to the host in the normal case; when the status is sent from the printer side at an interval of 1Qmsec, it is normally received by the host side, and a signal change according to the status is sent to the computer.

(bl is a case where a reception error occurs on the printer side while the power is already turned on, and when an error is received on the printer side interface [FPS2 * INPP
Turn the M signal on and off to reset the printer.

(C) is a case where a reception error occurs on the host side,
When the host side interface IFPSI receives an error, it turns off P +5V and ignores the status reception for 1 second.

As explained above, in the present invention, when an error is detected on either the printer side or the host side, the INP
The PM signal is turned on and the host side is notified that the printer side is off. Eventually, the power is restored to the power-on state by receiving normal data.

Furthermore, regarding the operation of the software, it is first necessary to make it compatible with existing software. Conventional software cannot reset the previously set contents unless the printer goes into an abnormal state. In the present invention, this abnormal state is notified to the software in the form of turning off the printer power, and when recovery occurs, the software resets the status value held by the software by notifying the printer power on. In this way, even if an error occurs from time to time, the software can be notified that the printer is abnormal. This allows the printer user to be notified. In addition, it becomes possible to reprint in the state that was previously used.6 [Effects of the Invention] As explained above, as an effect of using the high-speed serial interface of the present invention, there are +11 changes in the software interface. Therefore, conventional software can operate.

(2) No deterioration in performance occurs. In order to achieve a high transfer rate even for a serial interface, the overhead of the interface of the present invention is absorbed in the mechanical operation of the printer.

(3) Since error handling is strengthened, it is possible to guarantee the operation of the system.

(By using a 41LSI, it is possible to achieve smaller size and lower cost. Furthermore, since it is a serial interface, long-distance transmission technology such as balanced transmission of optical interface can be easily used, making it possible to lower the price and extend the connection distance, saving space. can be used effectively.

[Brief explanation of drawings]

Fig. 1 is a schematic connection block diagram between the host computer and printer of the present invention, Fig. 2 is a connection block diagram in which a serial-to-parallel conversion means is incorporated in the post computer of the present invention, and Fig. 3 Tal (b).
, (C) is a frame configuration diagram of the serial transmission procedure of the present invention, FIG. 4 is a printer side operation flowchart, FIG. 5 is a printer side state transition diagram, FIG. 6 is a host side operation flowchart, and FIG. 7 is a host side operation flowchart. State transition diagram, and FIGS. 8(a), (b), (C1 is an interface signal state explanatory diagram. (Explanation of symbols) H5T: host computer, IFPSI: host side parallel-serial conversion means , IFPS2...Printer side parallel-serial conversion means, PRT...Printer, PIF...Parallel interface, SrF...Serial interface, PSCll, PSCP...Parallel-serial conversion circuit, R/D, D /R...Driver/receiver.

Claims (1)

[Scope of Claims] 1. A printer serial interface system in which a high-speed serial interface is used as a printer interface for connecting a printer and a computer, wherein the high-speed serial interface is configured to operate when an error occurs on the high-speed serial interface. In some cases, the error is not treated as an abnormality in the printer, but the computer is notified that the printer is powered off, and the printer is instructed to reset the printer, and after a certain period of time has elapsed after the error was detected. , when the printer recovers from an error state, it notifies the computer that the power of the printer has been turned on again, and the computer resets the status of the printer. .