5250 Data Stream Details
Aid-generating keys
The AID (attention indicator) code identifies to the host system the function being requested from the keyboard. The AID code is returned by certain input operations when the operator presses an AID-generating key. The following table lists the AID-generating keys and the AID codes associated with each key. See Format of the Low-Level Environment Description for instructions on how to specify an alternative help key.
| AID Codes | ||
|---|---|---|
| AID key | Mnemonic | AID Code |
| Cmd 1 - 12 (cmd 1=x'31', cmd12=x'3C') | QSN_F1 - QSN_F12 | x'31' - x'3C' |
| Selector Light Pen Auto Enter | QSN_SLP | x'3F' |
| Forward Edge Trigger Auto Enter | QSN_FET | x'50' |
| PA1 | QSN_PA1 | x'6C' |
| PA2 | QSN_PA2 | x'6E' |
| PA3 | QSN_PA3 | x'6B' |
| Cmd 13 - 24 (cmd 13=x'B1', cmd24=x'BC') | QSN_F13 - QSN_F24 | x'B1' - x'BC' |
| Clear | QSN_CLEAR | x'BD' |
| Enter or Record Advance | QSN_ENTER | x'F1' |
| Help (not in error state) | QSN_HELP | x'F3' |
| Roll Down or Page Up | QSN_ROLLDOWN or QSN_PAGEUP | x'F4' |
| Roll Up or Page Down | QSN_ROLLUP or QSN_PAGEDOWN | x'F5' |
| QSN_PRINT | x'F6' | |
| Record Backspace | QSN_RECBS | x'F8' |
Control characters
The display control characters (CCs) are always specified as a pair of 1-byte fields. They are used on the QsnWTD, QsnReadInp, QsnReadMDT, and QsnReadMDTAlt APIs. These characters select specific operations for the display station to perform. Byte 1 is always processed first. When the CCs are used with the QsnWTD API, the first CC is processed immediately while the second CC is not processed until all the other information associated with the API has been processed. When used with an input operation, both CCs are processed after the operation has completed. The following two tables list the valid control character values and their associated mnemonics.
| Control Character Byte 1 | ||||||
|---|---|---|---|---|---|---|
| Mnemonic | Bits 0-2 | Reset Pending Aid; Lock Keyboard | Clear Master MDT; Reset MDT Flags in Nonbypass Fields |
Clear Master MDT; Reset MDT Flags in All Fields | Null Nonbypass Fields with MDT On | Null All Nonbypass Fields |
| QSN_CC1_ NULL | 000 | |||||
| QSN_CC1_ LOCKBD | 001 | x | ||||
| QSN_CC1_ MDTNBY | 010 | x | x | |||
| QSN_CC1_ MDTALL | 011 | x | x | |||
| QSN_CC1_ CLRMOD | 100 | x | x | |||
| QSN_CC1_MDTNBY_ CLRALL | 101 | x | x | x | ||
| QSN_CC1_MDTNBY_ CLRMOD | 110 | x | x | x | ||
| QSN_CC1_MDTALL_ CLRALL | 111 | x | x | x | ||
Note:
|
||||||
| Control Character Byte 2 | ||
|---|---|---|
| Mnemonic | Bit | Meaning |
| 0 | reserved | |
| QSN_CC2_NO_IC | 1 |
|
| QSN_CC2_RST_CSR_BL | 2 |
|
| QSN_CC2_SET_CSR_BL | 3 |
|
| QSN_CC2_UNLOCKBD | 4 |
|
| QSN_CC2_ALARM | 5 |
|
| QSN_CC2_MSG_OFF | 6 |
|
| QSN_CC2_MSG_ON | 7 |
|
Notes:
|
||
Screen attribute characters
The screen or field attributes control the image produced on the display station screen. Each attribute occupies one character position in the display station regeneration buffer and is displayed as a blank. The effect produced by an attribute begins at its location in the regeneration buffer and continues until the next attribute appears. The attributes for non-color displays are shown in the table below and for color displays in the Screen Attributes for Color Displays table. There are certain operations that allow a value to be specified for a screen attribute that indicates no screen attribute should be used. Where supported, the value is X'00' and the mnemonic is QSN_NO_SA.
| Screen Attributes for Non-Color Displays | ||
|---|---|---|
| Mnemonic | Bits | Value |
| QSN_SA_NORM | 0-2 | 001: Attribute identification flag |
| QSN_SA_CS | 3 |
|
| QSN_SA_BL | 4 |
|
| QSN_SA_UL | 5 |
|
| QSN_SA_HI | 6 |
|
| QSN_SA_RI | 7 |
|
| QSN_SA_ND | Non-display: equivalent to specifying QSN_SA_UL, QSN_SA_HI, and QSN_SA_RI. | |
| Note: Multiple functions can be selected by combining the mnemonics with a bitwise OR operation. | ||
| Screen Attributes for Color Displays | ||
|---|---|---|
| Mnemonic | Value | Meaning |
| QSN_SA_GRN | x'20' | Green |
| QSN_SA_GRN_RI | x'21' | Green/Reverse Image |
| QSN_SA_WHT | x'22' | White |
| QSN_SA_WHT_RI | x'23' | White/Reverse Image |
| QSN_SA_GRN_UL | x'24' | Green/Underscore |
| QSN_SA_GRN_UL_RI | x'25' | Green/Underscore/Reverse Image |
| QSN_SA_WHT_UL | x'26' | White/Underscore |
| QSN_SA_ND | x'27' | Nondisplay |
| QSN_SA_RED | x'28' | Red |
| QSN_SA_RED_RI | x'29' | Red/Reverse Image |
| QSN_SA_RED_BL | x'2A' | Red/Blink |
| QSN_SA_RED_RI_BL | x'2B' | Red/Reverse Image/Blink |
| QSN_SA_RED_UL | x'2C' | Red/Underscore |
| QSN_SA_RED_UL_RI | x'2D' | Red/Underscore/Reverse Image |
| QSN_SA_RED_UL_BL | x'2E' | Red/Underscore/Blink |
| QSN_SA_ND_2F | x'2F' | Nondisplay |
| QSN_SA_TRQ_CS | x'30' | Turquoise/Column Separators |
| QSN_SA_TRQ_CS_RI | x'31' | Turquoise/Column Separators/Reverse Image |
| QSN_SA_YLW_CS | x'32' | Yellow/Column Separators |
| QSN_SA_YLW_CS_RI | x'33' | Yellow/Column Separators/Reverse Image |
| QSN_SA_TRQ_UL | x'34' | Turquoise/Underscore |
| QSN_SA_TRQ_UL_RI | x'35' | Turquoise/Underscore/Reverse Image |
| QSN_SA_YLW_UL | x'36' | Yellow/Underscore |
| QSN_SA_ND_37 | x'37' | Nondisplay |
| QSN_SA_PNK | x'38' | Pink |
| QSN_SA_PNK_RI | x'39' | Pink/Reverse Image |
| QSN_SA_BLU | x'3A' | Blue |
| QSN_SA_BLU_RI | x'3B' | Blue/Reverse Image |
| QSN_SA_PNK_UL | x'3C' | Pink/Underscore |
| QSN_SA_PNK_UL_RI | x'3D' | Pink/Underscore/Reverse Image |
| QSN_SA_BLU_UL | x'3E' | Blue/Underscore |
| QSN_SA_ND_3F | x'3F' | Nondisplay |
Display address
The display address is the address at which data is displayed or a field definition begins. This can be modified explicitly with a Set Output Address (QsnSetOutAdr) call, or implicitly with output operations, such as those associated with the Write Data (QsnWrtDta) API, that accept a cursor position. The 5250 Write to Display (WTD) command initializes the display address to row 1, column 1. Because each output operation contains a WTD command, this means that the display address is reset on each direct screen output operation.
Insert cursor address
The insert cursor (IC) order specifies the position of the cursor when the host system unlocks the keyboard and when the display station operator presses the Home key. The display address is not affected by this address. This can be set with the Insert Cursor (QsnInsCsr) API, and in some cases with the Set Cursor Address (QsnSetCsrAdr) API (only when the Move Cursor (MC) order is not supported).
Modified data tag (mdt) bit
There is a modified data tag (MDT) bit for each input field and a master MDT bit. These bits are used to determine which fields should be returned in response to the Read Modified Fields (QsnReadMDT), Read Modified Alternate (QsnReadMDTAlt), and Read Modified Immediate Alternate (QsnReadMDTImmAlt) APIs. The MDT bit for a field and the master MDT bit can be set using bit 4 of the field format word (see Format of the Field Format Word) on a Set Field (QsnSetFld) API. The master MDT bit and the MDT bit for a field are set on anytime the operator types into or alters a field on the display. Once the bits are set, only a control character for resetting them (see Control Character Byte 1), or a clear screen operation using the Clear Screen (QsnClrScr) API or a Start of Header order, can reset them.
Resequencing
Resequencing allows the control unit to return up to 128 input fields in any specified order. Resequencing is accomplished by chaining input fields together with Field Control Words specifying resequencing. (See Format of the Field Control Word and the 5250 data stream documentation for details.)
States and modes
The display station can be in one of several states (conditions), each with its accompanying modes (methods of operation). The following is a list of these states and their associated modes:
- Hardware error state
- Normal locked state
- Normal unlocked state
- Command mode
- Insert mode
- Data mode
- Power-on state
- Prehelp error state
- Post-help error state
- System services (SS) message state
- System request state
See the 5250 data stream documentation for a detailed explanation of each state and mode.
Dumping the 5250 data stream commands
If you wish to produce a dump of the 5250 data stream commands that are produced by the DSM APIs, you should create a physical file (using the CRTPF command) having a record length of 2000. Name the physical file QSNDEBUGF, and ensure that the QSNDEBUGF file exists in the library list. DSM will dump the 5250 data stream commands to that file.
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