HT16561 VFD Digital Clock

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1 VFD Digital lock Features VFD display 2 hour clock function MHz crystal oscillation Zero adjust function ntegrated voltage regulator permits wide 4V to 8V operating voltage range Four level contrast control function 44-pin QFP package General Description The HT656 provides direct drive to VFD panels to implement a 2 hour clock function. n addition to obtaining its time base from a MHz crystal oscillation source and in having a wide operating voltage, the device also contains a host of other features. These include a choice of adjustment modes, including single push increment or 2Hz fast forward functions. dditional features are provided in the form of Zero adjustment and four levels of contrast control. lock Diagram E J H. H G K O, E L E H + 5 $ " 6 J ) K J J 5 + K J H $ ) + ) , + J H J ) K J J 6 E ) K J J E K J + K J H $ K H + K J H ) 2, H 5 J, H 5 J, H E L H 2 + F, H E " " ) 2 " Rev.. May 24, 22

2 Pin ssignment " # $ % & ' ) " ) 2 " " "" " " " ' & % $ # " 6 $ # $ ' " " 3. 2 ) & % $ # " " # $ % & ' " " 2 ) " ) " "" " " " ' & % $ # " $ ", " # ' $ # $ * $ " " 3. 2 * & + % % + 6 & $ ' # " ) + " # $ % & ' " ) , $ " Pin Description Pin Name /O Description VDD O High voltage power supply pin. VSS Ground pin. DM llumination level control pins. ONT nternally connected to pull-down resistors. ONT2 / Z HS MS SE llumination level control pins. nternally connected to pull-up resistors. When the / pin is low, the internal circuits are reset. The reset pulse width should be more than 2s. nternally connected to a pull-up resistor. Zero adjustment pin. nternally connected to a pull-down resistor. Hour adjustment pin. nternally connected to a pull-down resistor. Minute adjustment pin. nternally connected to a pull-down resistor. Set enable pin. nternally connected to a pull-up resistor. OSO O rystal oscillator pin OS TEST, TEST2 test pin - should be left open or kept at a low level TEST3, TEST4 test pin - should be left open or kept at a high level 64Hz O 64Hz signal output pin for oscillation frequency adjustment a, a3 ~ b2, b4, c4 M, PM Hz O Segment output pins for VFD Rev.. 2 May 24, 22

3 pproximate nternal onnections ) 5 5, + 6 ) $ 6 " " ) E J H K J F K J 5 + E J H F K J bsolute Maximum Ratings Logic Supply Voltage...V SS.3V to V SS +6.5V Driver Supply Voltage...V SS.3V to V SS +2V High nput Voltage...V SS.3V to V +.3V Driver Output Voltage...V SS.3V to V DD Driver Output urrent (Grid Driver)...7m to +2m Operating Temperature...4 to+85 High Output Voltage...V SS.3V to V +.3V Driver Output urrent (Segment Driver) m to +2m Storage Temperature...55 to +5 Note: These are stress ratings only. Stresses exceeding the range specified under bsolute Maximum Ratings may cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. Recommended Operating onditions Symbol Parameter Min. Typ. Max. Unit V DD Power Supply Voltage 4 8 V f OS Oscillation Frequency MHz t OP Operating Temperature 4 85 Rev.. 3 May 24, 22

4 D.. haracteristics V DD 6.V, V SS V, Ta4~85 Test onditions Symbol Parameter V DD onditions Min. Typ. Max. Unit V H High nput Voltage 6V 4.3 V V L Low nput Voltage 6V. V H Hi-level nput urrent 6V V V DD for TEST, TEST2, Z, MS, HS, DM, ONT 3 5 L V V ss for TEST3, TEST4 2 8 L2 Low-level nput urrent 6V V V ss for / 3 2 L3 V V ss for SE, ONT2 3 5 V OL Low-level Output current 6V OL V SS for all pin 5.9 V V OH Hi-level Output current 6V OH V SS for 64Hz pin. V OH Output urrent 6V V OH4.V for Hz, a2, d2, a4, d4, e4, g4 OL Output urrent 6V V OLV for Hz, a2, d2, a4, d4, e4, g4 OH2 Output urrent 6V V OH4.V, Other segment output pins except above OL2 Output urrent 6V V OLV SS, Other segment output pins except above 2 OH3 Output urrent 6V V OH 5.5V for 64Hz pin OL3 Output urrent 6V V OL.5V for 64Hz pin DD Dynamic urrent onsumption 6V f OS4.9434MHz, No load, N 39pF5%,.8 m 2V OUT 33pF5%, 75%.6 m haracteristics urves V DD vs DD haracteristics urve Ta25,, ),, L, 8, + D H J H E J E + K H L # # # " $ & " $ & 8 Rev.. 4 May 24, 22

5 Functional Description VFD Display Driving The device can directly drive VFD clock panels dynamically. The clock will be displayed in a 2-hour format with the hours ranging from to 2 and and minutes from to 59. f the most significant numeral is zero then the display will be extinguished. Segment connections 7-segment display is shown below showing the illumination pattern for each numeral. -., / ) + * % 5 J s the device is designed for clock applications, four 7-segment displays are required to display the correct time output. The connections for the segments are shown below, however it should be noted that the fourth segment only requires two of its segments to be driven. Other Pin Functions The external reset pin / is used to reset the internal circuit of the device. When this pin is pulled low the device will be reset, when the pin is allowed to go high, via its internal pull-high resistor, then the display will indicate a : output. n the open status, the SE pin is held to high level by a pull-high resistor, enabling the inputs from MS, HS and Z pins. These inputs become invalid by setting this pin to a low level externally. The 64Hz pin allows monitoring of the system frequency to allow frequency adjustments to be executed. s the name suggests, this output pin will continuously output a frequency of 64Hz. n the open status, the TEST and TEST2 pins are kept at a level by pull-down resistors. n the open status, the TEST3 and TEST4 pins are kept at a level by pull-up resistors. The Test pin function is as shown in the following table. ) " 2 " E E J " E E J E E J E E J TEST select function Switch Pin Name TEST TEST2 TEST3 Operating mode Normal function (Pulse) (Pulse) nput pulses to the 6.384KHz system of the circuit. nput pulses to the 6.384KHz system of the circuit. (Pulse) nput pulses to the 64Hz system of the circuit. (Pulse) nput pulses to the 64Hz system of the circuit. (Pulse) nput pulses for the minute and hour counters, which advances count with pulse. No carry functions for hour and minute counters. TEST select function 2 Switch Pin Name TEST3 DM ONT ONT2 (Pulse) * * Operating mode The pulse widths of the all segment outputs are controlled by the pulse width of the DM signal * * Sets all segment outputs to high impedance Note: * ndicates that the input level can be and Rev.. 5 May 24, 22

6 Three illumination level set pins, DM, ONT and ONT2 are provided to give control over the display brightness level, as shown in the following table. Switch Pin Name DM ONT ONT2 * * % duty display 25% (/4) duty display at 496Hz 2.5% (/8) duty display at 496Hz Note: high level, low level, * dont care Operating mode 6.25% (/6) duty display at 496Hz Device Functions Reset lthough the device is provided with an external reset pin /, the device will in fact reset itself when power is applied, eliminating the need for external reset components. The usual provision of an external capacitor is not required as an internal reset capacitor is integrated within the device. hatter removal The device contains circuits which are connected to input pins HS, MS and Z to remove chatter of less than 3.25ms. Oscillator The basic time base frequency for this device is determined by an external MHz crystal. When an external crystal along with two small external capacitors are connected to the two oscillator pins, the internal oscillator circuit will ensure generation of the correct time base signals. The oscillation frequency, although determined by the external crystal frequency, will also be influenced by the external capacitors, the crystal inherent capacitance and the residual capacitance of the external P tracks. To ensure accurate frequency generation, the crystal specification should be taken into account and care taken to place the external capacitors and crystal as close to the device as possible. Time djustment Operation Hour/minute adjustment oth the minutes and hour displays can be adjusted separately or both together in a fast forward format. The hour set pin, HS, and the minutes set pin, MS, are used to make these adjustments. oth of these pins are connected to internal pull-low resistors. Each time one of these lines is pulled high, the respective hour or minute value will increment by one, also if the line is continuously held high then the respective value will increment automatically at a rate of 2Hz. oth values will increment together if both lines are pulled high simultaneously. Note that no carry functions will be implemented when either the hour or minute value overflows. Zero adjustment zero adjust function is also included within the device and is controlled by the Z pin. This pin is connected to an internal pull low resistor. Pulling this line high will reset both the internal minutes and seconds value, however the way in which the display is reset depends upon the present value of display. f the minute value is presently less than 3 the only the second and minute values will be reset to zero and the hour value remain unchanged. However if the minute value is presently at a value of 3 or higher then when the zero adjustment function is executed, a carry will be implemented and the hour value will be increment by one. The following table illustrates a few examples of this operation. Present Time Zero djust Examples fter Zero djust Hr. Min. Sec. Hr. Min. Sec Rev.. 6 May 24, 22

7 pplication ircuits ), + 6 " ) ), + 6 " ) " " ) $ " ; " ' " " + " " ) J J E 6 O F + 8., Note: apacitors and 2 can adjust the frequency accuracy Rev.. 7 May 24, 22

8 Package nformation Note that the package information provided here is for consultation purposes only. s this information may be updated at regular intervals users are reminded to consult the Holtek website for the latest version of the package information. 44-pin QFP (mmmm) Outline Dimensions +, / ". ) * - " " Symbol Dimensions in inch Min. Nom. Max D E.3 F.2 G H.6..2 J K.4.8 L.4 7 Symbol Dimensions in mm Min. Nom. Max D 9.9. E.8 F.3 G H J K..2 L. 7 Rev.. 8 May 24, 22

9 Holtek Semiconductor nc. (Headquarters) No.3, reation Rd., Science Park, Hsinchu, Taiwan Tel: Fax: Holtek Semiconductor nc. (Taipei Sales Office) 4F-2, No. 3-2, YuanQu St., Nankang Software Park, Taipei 5, Taiwan Tel: Fax: Fax: (nternational sales hotline) Holtek Semiconductor nc. (Shenzhen Sales Office) 5F, Unit, Productivity uilding, No.5 Gaoxin M 2nd Road, Nanshan District, Shenzhen, hina 5857 Tel: , Fax: Holtek Semiconductor (US), nc. (North merica Sales Office) Fremont lvd., Fremont, Tel: Fax: opyright 22 by HOLTEK SEMONDUTOR N. The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holteks products are not authorized for use as critical components in life support devices or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at Rev.. 9 May 24, 22

Built-in LCD display RAM Built-in RC oscillator

PAT No. : TW 099352 RAM Mapping 488 LCD Controller for I/O MCU Technical Document Application Note Features Operating voltage: 2.7V~5.2V Built-in LCD display RAM Built-in RC oscillator R/W address auto