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feature

8 0.200" dot matrix characters, red, yellow, high-efficiency red, green, high-efficiency green, or soft orange Built-in 128 -character ROM, programmable mask for custom fonts readable from 8 feet (2.5 meters) Built-in decoder , Multiplexer and driver wide viewing angle, X-axis ±55°, Y-axis ±65°

Programmable Functions: – Single Blinking Character – Full Screen Blinking – Multi-level Dimming and Blanking – Clear Function – Self-Test

Internal or external clock

End stackable dual in-line plastic packaging

Literacy

16 user definable characters

illustrate

The HDSP2110S (red), HDSP2111S (yellow), HDSP2112S (high efficiency - dark red, HDSP2113S (green), HDSP2114S (high efficiency) green and HDSP2115S (soft orange) are 8-bit, 5x7 dot matrix, alphanumeric smart display devices. 0.20" high The numbers are packaged sturdy, high quality, optically clear, 0.6" lead split, 28-pin plastic dip. The onboard CMOS has a built-in 128-character ROM. The HDSP211XS also features a User-Definable Character (UDC) function which allows storage of 16 characters using RAM of arbitrary characters, symbols or icons with user-definable software. The character ROM itself is mask programmable and can be easily modified by the manufacturer to provide specified custom characters. The HDSP211XS is designed for standard microprocessor interfaces technology, fully compatible with TTL. Clock I/O and clock select pins allow users to cascade multiple display modules.

Maximum Ratings (tons) a = 25°(3) DC supply voltage, (max voltage, no LED illuminated) -0.3 to +7.0 VDC

Input Voltage Levels, All Inputs -0.3 to V Operating Temperature - 40C to 85C Class Storage Temperature -40C to 100°

Relative humidity (non-condensing) 85% working voltage, (maximum voltage 20 points / digital on) 5.5 V

Maximum Soldering Temperature (0.063" below seat surface, t < 5 seconds) ESD protection at 2601.5 K Ω, 100 psi Z-axis = 4 KV (per pin)

Switch Specifications (over operating temperature range and V cocos = 4.5 volts)

Cascade display

The HDSP211XS oscillator can drive up to 16 HDSP211XSs with a 15 pF input load per input. The following are the general requirements for cascade 16 displayed together: Determine the correct address for each display. Use CE in the address decoder to select the correct display. Select one monitor to provide the clock display to the other monitor. Connect CLKSEL to V Cocos for this exhibit. Connect CLKSEL to ground on other displays. Use RTS to synchronize blinking between monitors.

Function description

The display's user interface is organized into five memory areas. Use Flash input, FL and address lines, A3 and A4. All listed RAMs and registers can be read or written via the data bus. See Table 1. Each input pin states in the pin definition that RST can be used at power up or during normal operation. After booting, the RST will clear the flash RAM and control word register (00H) and reset the internal -nal counter. All 8 display memory locations will be set to a 20 hour blank to display all numbers. The FL pin allows access to flash RAM. The flash will set (D0=1) or reset (D0=0) the address character flashing as per A0-A2. The 1x8 bit control word register is loaded with attributes and data if A3=0. The control word logic implements the appropriate decoding of the attribute data. Character ROM is designed for 128 ASCII characters. This ROM is programmable with custom font masks. The clock source could be an internal oscillator (CLKSEL=1) device or an external clock (CLKSEL=0) could be another HDSP211X display's input to syn - the timing of the blinking of multiple displays. The display multiplexer controls the line driver, so there is no addi - the display system needs logic. The display has eight digits. Each figure has 35 LED clusters turned into a 5x7 dot matrix.

theory of operation

The HDSP211XS programmable display is designed to work with all major microprocessors. Data input is through an 8-bit parallel bus. The three-bit address routes data to the correct number location in RAM. Standard control signals such as WR and CE allow data to be written to the display. Data bits D0–D7 are used for character RAM and control word data input. A3 acts as a mode selector. If A3=1, character RAM is selected. Input data bit D7 will then determine whether input data bits D0–D6 are ASCII encoded data (D7=0) or UDC data (D7=1). See the UDC Address Registration section - Registers and RAM. For normal operation, the FL pin should be held high. When FL is held low, flash memory can be accessed to set character blinking. The seven-bit ASCII code is decoded by the character ROM to generate column data. Sending 20 columns of data per display cycle requires 14 display cycles to write eight digits. The lines are multiplexed into two groups of seven lines each. Internal timing and control logic synchronize the representation of the turning with respect to row and column data to ensure display operation. After a power-up sequence, the monitor will turn on randomly. So - playback should be reset after power up. A reset will clear the flash memory, control word registers and reset the internal counters. All figures will be displayed blank and the display brightness level will be 100%. Only three clock pulses can go into the display after RIS (at least 110 microseconds using the internal clock) - the edge of the reset line.

Microprocessor interface

The interface to the microprocessor is via an 8-bit data bus (D0–D7), a 4-bit address bus (A0–A3), and control lines FL, CE, and WR. To write data (ASCII/control word) to the monitor, CE should be held low, the address and data signals are stable, and WR is de-asserted. Data is written on low-to-high transfers - total weight. The control word is controlled by the control word decoding logic. Each code has a different function. Display code brightness changes the duty cycle of the column driver. This peak LED current remains the same, but the average LED current decreases according to the intensity level. Used Memory A2–A0 Data Bits FL A2 A3 Segment 0 X Flash RAM Character Address D01 0 0 UDC Address Register Don’t Care D3–D01 0 1 UDC RAM Row Address D4–D01 1 Character RAM Character Address D7–D0110 Control Word The registers don't care about the D7–D0 character flash enable cause the counter will be used with the column drive signal and cause the column drive to cycle at 2 Hz. So the characters blink at 2 Hz. Display Blink works the same as Blink Enable, but cycles all 20 column drivers at 2 Hz so that - makes all eight digits blink at 2 Hz. The IC's self-test function consists of two internal rou-triggered LEDs that run the main part of the IC and illuminate all the LEDs. The clear bit clears the character RAM and writes a blank to the display memory. But it doesn't clear the control word. ASCII data or control word data can be written to the display at this point. For multi-display operation, CLK I/O must be the correct choice. If CLKSEL=1, or enable external clock input CLKSEL=0.

character RAM

When FL, A4 and A3 are set to 1, 1, 1 is in a read or write cycle. Character RAM is 8 x 8 bit RAM, each of the 8 positions corresponds to a number on the display. The number 0 is on the left side of the display and the number 7 is on the right side of the display. Address line, A2–A0 selects the digital address where A2 is the most significant bit and A0 is the least significant bit. The two types of data stored in the character RAM are ASCII encoded data and UDC address data. The type of data stored in the character RAM is determined by data bit D7. If D7 is low, then the ASCII encoded data is stored in data bits D6–D0. If D7 is high, the UDC address data is stored in data bits D3–D0. ASCII-encoded data is a 7-bit code used to select 128 ASCII characters permanently stored in ASCII ROM. The UDC address data is a 4-bit code that selects the UDC character in UDC RAM. Up to 16 characters are available. See Fig. UDC Address Register and UDC RAM The UDC Address Register and UDC RAM allow the user to generate and store up to 16 custom characters. Each custom character is defined in a 5x7 dot pattern. To write 8 word cycles to define a custom character, one cycle to load the UDC address register and 7 cycles to define the character. Cheater - The tent of the UDC address register will store a 4-bit address for one of the 16 UDC RAM locations. UDC RAM is used to store custom characters.

UDC address register

The UDC address register is selected by setting FL=1, A4=0, and A3=0. It is a 4-bit register that uses data bits D3–D0 to store the 4-bit address code (ignore D7–D4). The address code selects one of 16 UDC RAM locations for a custom character generation. UDC memory selects UDC RAM by setting FL=1, A4=0, A3=1. This RAM consists of a 7x5 bit RAM. As shown in the figure, the address line, A2–A0, selects a line from the 7 lines of the custom character. The data bits, D4–D0, determine each row of 5 bits of column data. Each data bit corresponds to an LED. If the data bit is high, the LED is on. If the data bit is low, the LED is off. To create a character, each of the 7 rows of column data needs to be defined. The logic is shown in Figures 9 and 10. Flash Flash RAM allows the display to flash one or more characters being displayed. Flash Ram is accessed by set-minimum flight level. A4 and A3 are ignored. Flash memory is 8x1 bits of RAM with each bit corresponding to a numeric address. The number 0 is on the left side of the display and the number 7 is on the display. Address line, A2–A0 select number address A2 is the most significant bit and A0 is the least significant bit - my number. Data bit D0, sets and resets each digit. When D0 is high, the flash bit is set, and when D0 is low, the flash bit is reset. See Fig.

control word

The control word is used to set the user. Addressed by setting FL=1, A4=1, A3=0. This control word is an 8-bit register, accessed using the data bits, D7–D0. See Figures 12 and 13-Troll for logic and properties con. The control word has 5 functions. They are Bright Control, Blink Character Enable, Blink Character Enable, Self Test and Clear (Flash and Character RAM only). Brightness control control word bits, D2–D0, control the brightness of the display. Binary code 000 is 100% brightness, and 111 is blank. See Figure 13 code for brightness level vs binary. The average Icc can be calculated by multiplying the 100% brightness level I level CC value (by monitor brightness). For example, when a display set to 80% brightness has a 100% average Icc value of 200 mA, the average Icc value is 200 mA x 80% = 160 mA. Flash function control word bit D3, enables or disables the flash function. When D3 is 1, the flash function is enabled, and any number it sets the corresponding bit in the flash RAM will flash on approach - about 2 Hz. When using an external clock, the flash frequency can be determined by dividing the clock rate by 28672. When D3 is 0, the Flash function is disabled and the contents of the Flash RAM are ignored. For synchronized blinking on multiple monitors, see the Reset section.

Blink function

Control word bit D4, enables or disables the blinking function. When D4 is 1, the blinking function is enabled and all character displays will blink at approximately 2 Hz. Blink function - if both functions are enabled. When D4 is 0, the blinking function is disabled. when? With an external clock, this can be done by dividing the clock rate by 28672. For simultaneous blinking of multiple displays, see Reset section.

self-test

Reset must be activated before starting the self-test. Control word bits D6 and D5 are used for the self-test function. When D6 is 1, start self-test. The self-test result is stored in bit D5. Control word bit D5 is a read-only bit. When D5 is 1, it means that the self-check is passed. When D5 is 0, Self indicates that the test failed. The integrated circuit's self-test function includes one of two internal procedures and turns on all LEDs. The first program loops through all states of the ASCII decoder ROM and performs a summation of the check output. D5 is set to 1 if the check amount matches the correct value.

The second routine uses

Drive circuit. This is done by writing squares and reversing the square pattern to the display. Each mode was dis-played for about 2 seconds. During the self-test function - access to the display is prohibited. The time required to perform the self-test function is by multiplying the clock time by 262144 (typical time ≈ 4.6 seconds). At the end of the self-test function, the Character RAM Load Blank Control Word Register is set to zeros other than D5, and the FlashRAM is cleared and the UDC Address Register is set to all 1s. The clear function (see Figures 13 and 14) controls the word bit, D7 clears the character RAM to 20 hex and the flash is all zeroed. Rams are cleared within three minutes when D7 is set to 1. During the clearing time, the display has to be accessed. The control word RAM will be reset to "0" when the clear function is complete. RESET FUNCTION The display should be reset (RST=low) after power-up. When the display is reset, the character RAM, flash memory and control word registers are cleared. The display's internal counter is reset. The reset period is three clock cycles (using the internal clock). No access to the display is allowed during this time. To synchronize the flickering and flickering of multiple displays, it is the displays that use a common clock source and reset all displays at the same time to start the counters inside the same location. When RST is low, RD cannot access display nor WR

Optical Considerations

The high .200" characters of the HDSP211XS improve readability up to eight feet. Proper filter selection improves readability this distance. Use filters to emphasize contrast between LEDs as well as character backgrounds. This increases discrimination - Actions for different characters. The only limitation is cost. Accept the cost-benefit ratio considering the best ambient lighting ambient filters. Incandescent (with almost no green) or fluorescent (with almost no red) light does not have a flat spectral response to sunlight. A plastic bandpass filter is an inexpensive and effective - aggressive way to enhance contrast. The HDSP2110/2112S are red/high efficiency red displays and should be used with a long wavelength pass filter in the 570nm to 590nm range. The HDSP2113S should be used with a yellow-green bandpass Matches filters that peak at 565nm. For multi-color displays, the neu-tral density gray filter provides the best compromise. Additional contrast enhancement can be obtained by shading the dis-play. Built-in Plastic bandpass filter for shutters Contrast improvement next step. The plastic filter can be further improved with an anti-reflective coating to reduce glare. The trade-off is blurred characters. Mounting the filter close to the display reduces this effect. Be careful not to Overheating plastic filter that allows proper air flow. Use circular filter for best filter enhancement polarization, anti-reflection, bandpass filter. Circular pole - by reducing the light passing through the filter and reflecting off the display less 1%. Several filter manufacturers offer high-quality filter materials.