Then the OUT goes high, and remains high until a new count is there or a new Mode 0 control word is written into the counter. It will remain low until the counter reaches 0, it is decremented by 1 after each clock cycle. After writing the control word, OUT is low at first. Now let us see those six operating modes of 8254 chip: Mode If this is 0, it will act like binary counter, otherwise it will act like BCD counter. The last bit (LSb) of the control word is used to select whether the counting will be in Binary or BCD. Three bits of M2, M1 and M0 are used to decide programming modes. Read or Write lower byte followed by upper byte The values of the RW1 and RW2 are used to denote the read and write operation. We can select the counter by the SC1 and SC0. The structure of the counter is like this - 7 We do not need to program some unused counters.Ĭounters are programmed by writing the control words and then one initial count.

The mode, count value, and outputs are undefined in that time.Įach counter must be programmed before it is used. When the chip is powering up, the state is undefined. Select an item and use the up or down arrows to change the order, Press - to remove a selected item.ĭrop-down enabled Lets the user open the combo box and make selections.Here we will see the control words and the operation modes of the 8254 programmable interval timer chip.īefore discussing its operating modes and control word properties, we should know about some important facts of this chip. Items in drop-down list Shows your current list. Press + or Enter to add an item to the list. If there is default text, user text replaces it.ĭefault Value Choose between Not checked or checked as default.Ĭheckbox size Set a size Exactly or Auto to change size as needed.Ĭheck box enabled Lets the user check or clear the text box.ĭrop-down item Type in strings for the list box items. Text box enabled Lets the user enter text into a field. Text format can set whether text automatically formats to Uppercase, Lowercase, First capital, or Title case. Maximum length sets the length of text that a user can enter. Set Text box enabled to allow the user to enter text into the field. Type Select form Regular text, Number, Date, Current Date, Current Time, or Calculation.ĭefault text sets optional instructional text that's displayed in the text box before the user types in the field. Select Macro to Run on lets you choose a recorded or custom macro to run on Entry or Exit from the field.īookmark Set a unique name or bookmark for each control.Ĭalculate on exit This forces Word to run or refresh any calculations, such as total price when the user exits the field.Īdd Help Text Give hints or instructions for each field.Ĭancel Forgets changes and exits the panel. Select a control and then select Options to set up or make changes. Options let you set common settings, as well as control specific settings. For more info on sections, see Insert a section break. To do this, choose Select Sections in the Restrict Editing panel.

If you want to protect only parts of the document, separate the document into sections and only protect the sections you want. Open the form that you want to lock or protect.Īfter selecting restrictions, select Yes, Start Enforcing Protection. If you want to limit how much others can edit or format a form, use the Restrict Editing command: Select the content control that you want to change. For example, the Date Picker control offers options for the format you want to use to display the date. Set or change properties for content controlsĮach content control has properties that you can set or change. Select the Legacy Form control or Active X Control that you want to include. Go to Developer > Legacy Forms drop-down. Legacy form controls are for compatibility with older versions of Word and consist of legacy form and Active X controls.Ĭlick or tap where you want to insert a legacy control.

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