STANDARD RED SCF5740 HIGH EFFICIENCY RED SCF5742 HIGH EFFICIENCY GREEN SCF5744 0.270” 4-Character, 5x7 Dot Matrix Serial Input Dot Addressable Intelligent Display Package Dimensions in Inches (mm) .325 (8.26) .157 –.007 (3.99 –.18) .175 (4.45) .790 –.010 (20.07 –.25) .270 (6.86) 1.300 max. (33.02) Pin 1 Indicator .600 –.020 (15.25 –.51) Luminous Intensity Code EIA Date Code SCF574X SIEMENS Z YYWW .276 max. (7.0) max. .160 –.020 (4.06) –.51) .100 –.015 (2.54 –.38) .145 –.015 (3.68 –.38) .018 X .012 (.46 X .30) (Leads 22 plcs.) FEATURES • Four 0.270” (6.85 mm) 5 x 7 Dot Matrix Characters • • • • • • • in Red, High Efficiency Red, High Efficiency Green Optimum Display Surface Efficiency (display area to package ratio) High Speed Data Input Rate: 5 MHz ROMless Serial Input, Dot Addressable Display Ideal for User Defined Characters Built-in Decoders, Multiplexers and LED Drivers Readable from 6 Feet (1.8 meters) Wide Viewing Angle, X Axis ± 55°, Y Axis ± 55° Attributes – 140 Bit RAM for User Defined Characters – Eight Dimming Levels – Power Down Model (<250 µ W) – Hardware/Software Clear Functions – Internal or External Clock DESCRIPTION The SCF574X is a four digit, dot addressable 5x7 dot matrix, serial input, alphanumeric Intelligent Display. The four digits are packaged in a rugged, high quality, optically transparent, plastic 22 pin DIP with 0.1” pin spacing. The on-board CMOS has a 140 bit RAM, one bit associated with one LED, each to generate User Defined Characters. In Power Down Mode, quiescent current is <50 µA. The SCF574X is designed for work with the serial port of most common microprocessors. Data is transferred into the display through the Serial Data Input (DATA), clocked by the Serial Data Clock (SDCLK), and enabled by the Load Input (LOAD). The Clock I/O (CLK I/O) and Clock Select (CLK SEL) pins offer the user the capability to supply a high speed external multiplex clock. This feature can minimize audio in-band interference for portable communication equipment or eliminate the visual sychronization effects found in high vibration environments such as avionic equipment. 2–200 Switching Specifications (over operating temperature range and VCC=4.5 V to 5.5 V) Maximum Rating DC Supply Voltage ........................................ –0.5 to +7.0 Vdc Input Voltage Levels Relative to Ground................................................–0.5 toVCC+0.5 Vdc Operating Temperature ................................. –40°C to +85°C Storage Temperature .................................... –40°C to +100°C Maximum Solder Temperature 0.063" below Seating Plane, t<5 sec...................................... 260°C Relative Humidity at 85°C................................................. 85% Maximum Number of LEDs at 100% Brightness ................. 64 Maximum Power Dissipation ........................................ 0.65 W ESD (100 pF, 1.5 KΩ)........................................................2 KV Maximum Input Current .............................................± 186 mA Symbol Description Min. Units TRC Reset Active Time 600 ns TLDS Load Setup Time 50 ns TDS Data Setup Time 50 ns TSDCLK Clock Period 200 ns TSDCW Clock Width 70 ns TLDH Load Hold Time 0 ns TDH Data Hold Time 25 ns TWR Total Write Time 2.2 µs TBL Time Between Loads 600 ns Note: TSDCW is the minimum time the SDCLK may be low or high. The SDCLK period must be a minimum of 200 ns. T LDS LOAD T DS DATA TLDH D0 D7 TDH SDCLK T SDCW T SDCLK Figure 1. Timing diagram–Data write cycle TWR TBL LOAD SDCLK DATA D0 D1 D2 D3 D4 D5 D6 D7 D0 D4 D5 D6 D7 D0 OR LOAD SDCLK DATA D0 D1 D2 D3 Figure 2. Timing diagram–Instruction cycle SCF5740/2/4 2–201 Electrical Characteristics (over Operating Temperature) Parameter Min. Typ. Max. Units 4.5 5.0 5.5 V 50 µA VCC=5 V, all inputs=0 V or VCC 186 mA VCC=5 V, “#” displayed in all 4 digits at 100% brightness at 25°C IIL Input current –10 µA VCC=5 V, VIN=0 V (all inputs) IIH Input current +10 µA VCC=VIN=5.0 V=0 V (all inputs) V VCC=4.5 V to 5.5 V V VCC=4.5 V to 5.5 V VCC ICC (Pwr Dwn Mode)(4) ICC 4 digits 20 dots/character 150 VIH 3.5 VIL 1.5 Conditions IOH (CLK I/O) –28 mA VCC=4.5 V, VOH=2.4 V IOL (CLK I/O) 23 mA VCC=4.5 V, VOL=0.4 V θJC-PIN 32 °C/W Fext External Clock Input Frequency 120 347 KHz VCC=5.0 V, CLKSEL=0 Fosc Internal Clock Input Frequency 120 347 KHz VCC=5.0 V, CLKSEL=1 Clock I/O Bus Loading 240 pF Clock Out Rise Time 500 ns VCC=4.5 V, VOH=2.4 V Clock Out Fall Time 500 ns VCC=4.5 V, VOH=0.4 V 1086 Hz FM, Digit 375 768 Notes 1. Peak current 5/3 x ICC. 2. Unused inputs must be tied high. 3. Contact Siemens for 3.3 volt operation. 4. External oscillator must be stopped if being used to maintain an ICC <50µA. Input/Output Circuits Figures 3 and 4 show the input and output resistor/diode networks used for ESD protection and to eliminate substrate latch-up caused by input voltage over/under shoot. VCC VCC input input/output 1 KΩ 1 KΩ GND Inputs GND Clock I/O Figures 3 and 4. SCF5740/2/4 2–202 Optical Characteristics at 25°C VCC=5.0 V at 100% Brightness Level, Viewing Angle: X Axis ± 55°, Y Axis ± 65° Red SCF5740 Description Symbol Min. Typ. Units Luminous Intensity per dot IV 55 Peak Wavelength λ(peak) 655 nm Dominant Wavelength λ(d) 639 nm Typ. Units µcd/dot High Efficiency Red SCF5742 Description Symbol Min. Luminous Intensity per dot IV 110 Peak Wavelength λ(peak) 630 nm Dominant Wavelength λ(d) 626 nm Typ. Units µcd/dot High Efficiency Green SCF5744 Description Symbol Min. Luminous Intensity per dot IV 110 Peak Wavelength λ(peak) 568 nm Dominant Wavelength λ(d) 574 nm µcd/dot Notes 1. Dot to dot intensity matching at 100% brightness is 1.8:1. 2. Displays within a given intensity category have an intensity matching of 1.5:1 (max.) SCF5740/2/4 2–203 Pin Definitions Top View 22 Pins Digit 0 Digit 1 1 12 Digit 2 Pin Function 1 N/C 2 GND 3 N/C 4 N/C 5 N/C Digit 3 6 N/C 11 7 N/C 8 N/C Pins Pin Assignment Definitions Power supply ground 9 VLL LED supply 10 VCC Logic supply N/C 11 N/C 21 CLKSEL 12 N/C N/C 20 CLK I/O 13 LOAD 4 N/C 19 RST 5 N/C 18 N/C Low input enables data clocking into 8bit serial shift register. When load goes high, the contents of 8-bit serial shift register will be decoded. 6 N/C 17 N/C 14 DATA Serial data input 7 N/C 16 N/C 15 SDCLK For loading data into the 8-bit serial data register 8 N/C 15 SCLK 16 N/C 9 VLL 14 DATA 17 N/C 10 VCC 13 LOAD 18 N/C 11 N/C 12 N/C 19 RST Asynchronous input, when low clears the multiplex counter, address register, control word register, user RAM and data registe. Control word register is set to 100% brightness. The display will be blank. 20 CLK I/O Outputs Master Clock or inputs External Clock 21 CLKSEL High=Internal Clock (Master) Low=External Clock (Slave) 22 N/C Pin Function Pin Function 1 N/C 22 2 GND 3 0.043 (1.09) typ. 0.175 (4.45 C1 C2 C3 C4 C5 R0 R1 R2 R3 R4 0.270 (6.86) R5 0.009 (0.23) typ. R6 0.045 (1.14) typ. Dimensions in inches (mm) Tolerance: .XXX ± .010 (.25) Figure 5. Dot Matrix Format SCF5740/2/4 2–204 Display Column and Row Format C 0 C 1 C 2 C 3 C 4 Row 0 1 1 1 1 1 Row 1 0 0 1 0 0 Row 2 0 0 1 0 0 Row 3 0 0 1 0 0 Row 4 0 0 1 0 0 Row 5 0 0 1 0 0 Row 6 0 0 1 0 0 Operation of the SCF574X The SCF574X display consists of a CMOS IC containing control logic and drivers for four 5x7 characters. Theres components are assembled in a compact plastic package. 1=Display dot “On” 0=Display dot “Off’ Individual LED dot addressability allows the user great freedom in creating special characters or mini-icons. The serial data interface provides a highly efficient interconnection between the display and the mother board. The SCF574X requires only three lines as compared to 14 for an equivalent four character parallel input part. The on-board CMOS IC is the electronic heart of the display. The IC accepts decoded serial data, which is stored in the internal RAM. Asynchronously the RAM is read by the character multiplexer at a strobe rate that results in a flicker free display. Figure 6 shows the three functional areas of the IC. These include: the input serial data register and control logic, a 140 bits two port RAM, and an internal multiplexer/display driver. Column Data Ranges Row 0 00H to 1FH Row 1 00H to LFH Row 2 00H to LFH Row 3 00H to LFH Row 4 00H to LFH Row 5 00H to LFH Row 6 00H to LFH RST –•• 64 Counter Y Address Decode Data SDCLK Load OSC 8 Bit Serial Register CLK I/O CLKSEL –•• 7 Counter Mux Rate Row Control Logic and Row Drivers Rows 0 to 6 Column Drivers Digit 0 to 4 Columns User RAM Memory 0 to 20 Display 0 1 2 3 7x20 Bits X Address Decode 3 Bit Address Register 6 Bit Control Word Register Control Word Logic V1 V2 VDIM Controls Figure 6. Block Diagram SCF5740/2/4 2–205 The following explains how to format the serial data to be loaded into the display. The user supplies a string of bit mapped decoded characters. The contents of this string is shown in Figure 7a. Figure 7b shows that each character consist of eight 8 bit words. The first word encodes the display character location and the succeeding seven bytes are row data. The row data represents the status (On, Off) of individual column LEDs. Figure 7c shows that each 8 bit word is formatted to represent Character Address, or Column Data. Table 7 shows the Row Address for the example character “D.” Column data is written and read asynchronously from the 140 bit RAM. Once loaded the internal oscillator and character multiplexer reads the data from the RAM. These characters are row strobed with column data as shown in Figures 8 and 9. The character strobe rate is determined by the internal or user supplied external MUX Clock and the IC’s ÷ 320 counter. Table 7. Character “D” Figure 7d shows the sequence for loading the bytes of data. Bringing the LOAD line low enables the serial register to accept data. The shift action occurs on the low to high transition of the serial data clock (SDCLK). The least significant bit (D0) is loaded first. After eight clock pulses the LOAD line is brought high. With this transition the OPCODE is decoded. The decoded OPCODE directs D4–D0 to be latched in the Character Address register, stored in the RAM as Column data, or latched in the Control Word register. The control IC requires a minimum 600 ns delay between successive byte loads. As indicated in Figure 7a, a total of 256 bits of data are required to load all four characters into the display. Op code D7 D6 D5 The Character Address Register bits, D4–D0 (Table 2), and Row Address Register bits, D7–D5 (Table 3), direct the Column Data bits, D4–D0 (Table 3) to specific RAM location. Column Data D4 D3 D2 D1 D0 C0 C1 C2 C3 C4 Hex Row 0 0 0 0 1 1 1 1 0 1E Row 1 0 0 0 1 0 0 0 1 11 Row 2 0 0 0 1 0 0 0 1 11 Row 3 0 0 0 1 0 0 0 1 11 Row 4 0 0 0 1 0 0 0 1 11 Row 5 0 0 0 1 0 0 0 1 11 Row 6 0 0 0 1 1 1 1 0 1E Example: Serial Clock = 5MHz, Clock Period = 200ns 352 Clock Cycles, 70.4 µs a. Character 0 Character 1 Character 2 Character 3 88 Clock Cycles, 17.6 µs b. Character 0 Address Row 0 Column Data Row 1 Column Data Row 2 Column Data 11 Clock Cycles, 2.2µs Character Address c. D7 1 D6 0 D5 1 D4 0 D2 0 D1 0 Row 4 Column Data Row 5 Column Data Row 6 Column Data 11 Clock Cycles, 2.2µs OPCODE D3 0 Row 3 Column Data D0 0 Time Between Loads 600ns(min) Column Data D7 0 D6 0 D5 0 D4 D OPCODE D3 D D2 D D1 D D0 D Time Between Loads 600ns(min) LOAD Serial Clock Clock Period DATA d. D0 D1 D2 D3 D4 D5 D6 D7 Time between LOADS t0 Figure 7a–d. Loading Serial Character Data SCF5740/2/4 2–206 The user can activate four Control functions. These include: LED Brightness Level, IC Power Down, Prescaler, or Display Clear. OPCODEs and six bit words are used to initiate these functions. The OPCODEs and Control Words for the Character Address and Loading Column Data are shown in Tables 2 and 3 . Table 4a. Display Brightness Table 2. Load Character Address Op code D7 D6 D5 Character Address D4 D3 D2 D1 D0 Hex Operation Load Hex Operation Level 0 E0 100% 0 1 E1 53% 0 1 0 E2 40% 0 0 1 1 E3 27% 0 0 1 0 0 E4 20% Op code D7 D6 Control Word D5 D4 D3 D2 1 1 1 0 0 0 0 1 1 1 0 0 0 1 1 1 0 0 1 1 1 0 1 1 1 D1 D0 1 0 1 0 0 0 0 0 A0 Character 0 1 1 1 0 0 1 0 1 E5 13% 1 0 1 0 0 0 0 1 A1 Character 1 1 1 1 0 0 1 1 0 E6 6.6% 1 0 1 0 0 0 1 0 A2 Character 2 1 1 1 0 0 1 1 1 E7 0.0% 1 0 1 0 0 0 1 1 A3 Character 3 Hex Operation Level Table 4b. Display Brightness Table 3. Load Column Data Op code D7 D6 D5 Column Data D4 D3 D2 D1 D0 Operation Load 0 0 0 C0 C1 C2 C3 C4 Row 0 0 0 0 C0 C1 C2 C3 C4 Row 1 0 0 0 C0 C1 C2 C3 C4 Row 2 0 0 0 C0 C1 C2 C3 C4 Row 3 0 0 0 C0 C1 C2 C3 C4 Row 4 0 0 0 C0 C1 C2 C3 C4 Row 5 0 0 0 C0 C1 C2 C3 C4 Row 6 The user can select eight specific LED brightness levels, Table 4. Depending on how D3 is selected either one (1) for maximum peak current or zero (0) for 12.5% of maximum peak current in the control word per Table 4a and 4b, the user can select 16 specific LED brightness levels. These brightness levels (in percentages of full brightness of the display) depending on how the user selects D3 can be one (1) or zero (0) are as follows: 100% (E0HEX or E8HEX), 53% (E1HEX or E9HEX), 40% (E2HEX or EAHEX ), 27% (E3HEX or EBHEX ), 20% (E4HEX or ECHEX ), 13% (E5HEX or EDHEX), and 6.6% (E6HEX or EEHEX ), 0.0% (E7HEX or EFHEX ). The brightness levels are controlled by changing the duty factor of the row strobe pulse. Op code D7 D6 Control Word D5 D4 D3 D2 1 1 1 0 1 0 0 0 E0 100% 1 1 1 0 1 0 0 1 E1 53% 1 1 1 0 1 0 1 0 E2 40% 1 1 1 0 1 0 1 1 E3 27% 1 1 1 0 1 1 0 0 E4 20% 1 1 1 0 1 1 0 1 E5 13% 1 1 1 0 1 1 1 0 E6 6.6% 1 1 1 0 1 1 1 1 E7 0.0% D1 D0 The SCF574X offers a unique Display Power Down feature which reduces ICC to less than 50 µA. When EFHEX is loaded (Table 5) the display is set to 0% brightness. When in the Power Down mode data may still be written into the RAM. The display is reactivated by loading a new brightness Level Control Word into the display. Table 5. Power Down Op code D7 D6 Control Word D5 D4 D3 D2 D1 D0 Hex Operation Level 1 1 EF 0% brightness 1 0 1 1 1 1 1 Row 0 off LED Row 1 on LED Row 2 Previously “on” LED Row 3 Row 4 Row 5 Row 6 0 1 2 3 4 Columns Figure 8. Row and Column Locations for a Character “D” SCF5740/2/4 2–207 ROW LOAD LOAD ROW 0 LOAD ROW 1 LOAD ROW 2 LOAD ROW 3 LOAD ROW 4 LOAD ROW 5 LOAD ROW 6 Row 0 Row 0 Row 0 Row 0 Row 0 Row 0 Row 0 Row 1 Row 1 Row 1 Row 1 Row 1 Row 1 Row 1 Row 2 Row 2 Row 2 Row 2 Row 2 Row 2 Row 2 Row 3 Row 3 Row 3 Row 3 Row 3 Row 3 Row 3 Row 4 Row 4 Row 4 Row 4 Row 4 Row 4 Row 4 Row 5 Row 5 Row 5 Row 5 Row 5 Row 5 Row 5 Row 6 Row 6 Row 6 Row 6 Row 6 Row 6 0 1 2 3 4 Columns 0 1 2 3 4 Columns 0 1 2 3 4 Columns 0 1 2 3 4 Columns 0 1 2 3 4 Columns Row 6 0 1 2 3 4 Columns 0 1 2 3 4 Columns Figure 9. Row Strobing The SCF574X allows a high frequency external oscillator source to drive the display. Data bit, D4, in the control word format controls the prescaler function. The prescaler allows the oscillator source to be divided by 16 by setting D4=1. However, the prescaler should not be used, i.e., when using the internal oscillator source. Good ground (pin 2) and power supply decoupling (pins 9 and 10) will insure that Icc (<400 mA peak) switching currents do not generate localized ground bounce. Therefore it is recommended that each display package use a 0.1µF and 20 µF capacitor between VCC and ground. The Software Clear (C0HEX ), given in Table 6, clears the Address Register and the RAM. The display is blanked and the Character Address Register will be set to Character 0. The internal counter and the Control Word Register are unaffected. The Software Clear will remain active until the next data input cycle is initiated. When the internal MUX Clock is being used connect the CLKSEL pin to VCC. In those applications where RESET will not be connected to the system’s reset control, it is recommended that this pin be connected to the center node of a series 0.1, µF and 100 KΩ RC network. Thus upon initial power up the RESET will be held low for 10 ms allowing adequate time for the system power supply to stabilize. Table 6. Software Clear ESD Protection Op code D7 D6 1 1 Control Word D5 D4 D3 0 0 0 D2 0 D1 0 0 D0 Hex Operation C0 CLEAR Multiplexer and Display Driver The four characters are row multiplexed with RAM resident column data. The strobe rate is established by the internal or external MUX Clock rate. The MUX Clock frequency is divided by a 448 counter chain. This results in a typical strobe rate of 768 Hz. By pulling the Clock SEL line low, the display can be operated from an external MUX Clock. The external clock is attached to the CLK I/O connection (pin 9). The maximum external MUX Clock frequency should be limited to 1 MHz. An asynchronous hardware Reset (pin 8) is also provided. Bringing this pin low will clear the Character Address Register, Control Word Register, RAM, and blanks the display. This action leaves the display set at Character Address 0, and the Brightness Level set at 100%. ELECTRICAL & MECHANICAL CONSIDERATIONS The input protection structure of the SCF574X provides significant protection against ESD damage. It is capable of withstanding discharges greater than 2 KV. Take all the standard precautions, normal for CMOS components. These include properly grounding personnel, tools, tables, and transport carriers that come in contact with unshielded parts. If these conditions are not, or cannot be met, keep the leads of the device shorted together or the parts in anti-static packaging. Soldering Considerations The SCF574X can be hand soldered with SN63 solder using a grounded iron set to 260°C. Wave soldering is also possible following these conditions: Preheat that does not exceed 93°C on the solder side of the PC board or a package surface temperature of 85°C. Water soluble organic acid flux (except carboxylic acid) or resinbased RMA flux without alcohol can be used. Wave temperature of 245°C ± 5°C with a dwell between 1.5 sec. to 3.0 sec. Exposure to the wave should not exceed temperatures above 260°C for five seconds at 0.063" below the seating plane. The packages should not be immersed in the wave. Interconnect Considerations Optimum product performance can be had when the following electrical and mechanical recommendations are adopted. The SCF574X’s IC is constructed in a high speed CMOS process, consequently high speed noise on the SERIAL DATA, SERIAL DATA CLOCK, LOAD and RESET lines may cause incorrect data to be written into the serial shift register. Adhere to transmission line termination procedures when using fast line drivers and long cables (>10 cm). SCF5740/2/4 2–208 in the 570 nm to 600 nm range. The SCF5744 is a high efficiency green display and should be used with long wavelength pass filter that peaks at 565 nm. Post Solder Cleaning Procedures The least offensive cleaning solution is hot D.I. water (60°C) for less than 15 minutes. Addition of mild saponifers is acceptable. Do not use commercial dishwasher detergents. For faster cleaning, solvents may be used. Exercise care in choosing solvents as some may chemically attack the nylon package. For further information refer to Appnotes 18 and 19 in the current Siemens Optoelectronic Data Book. See Appnote 19, Table 1, “Displays–Group 2” for the SCDV554X. An alternative to soldering and cleaning the display modules is to use sockets. Naturally, 14 pin DIP sockets .300" wide with .100" centers work well for single displays. Multiple display assemblies are best handled by longer SIP sockets or DIP sockets when available for uniform package alignment. Socket manufacturers are Aries Electronics, Inc., Frenchtown, NJ; Garry Manufacturing, New Brunswick, NJ; Robinson-Nugent, New Albany, IN; and Samtec Electronic Hardward, New Albany, IN. For further information refer to Appnote 22 in the current Siemens Optoelectronic Data Book. Optical Considerations The 0.270" high character of the SCF574X gives readability up to five feet. Proper filter selection enhances readability over this distance. Using filters emphasizes the contrast ratio between a lit LED and the character background. This will increase the discrimination of different characters. The only limitation is cost. Take into consideration the ambient lighting environment for the best cost/benefit ratio for filters. Incandescent (with almost no green) or fluorescent (with almost no red) lights do not have the flat spectral response of sunlight. Plastic band-pass filters are an inexpensive and effective way to strengthen contrast ratios. The SCF5740 is a red display and should be used with long wavelength pass filter having a sharp cut-off in the 600 nm to 620 nm range. The SCF5742 is a high efficiency red display and should be used with long wavelength pass filter having a sharp cut-off Additional contrast enhancement is gained by shading the displays. Plastic band-pass filters with built-in louvers offer the next step up in contrast improvement. Plastic filters can be improved further with anti-reflective coatings to reduce glare. The trade-off is fuzzy characters. Mounting the filters close to the display reduces this effect. Take care not to overheat the plastic filter by allowing for proper air flow. Optimal filter enhancements are gained by using circular polarized, anti-reflective, band-pass filters. The circular polarizing further enhances contrast by reducing the light that travels through the filter and reflects back off the display to less than 1%. Several filter manufacturers supply quality filter materials. Some of them are: Panelgraphic Corporation, W. Caldwell, NJ; SGL Homalite, Wilmington, DE; 3M Company, Visual Products Division, St. Paul, MN; Polaroid Corporation, Polarizer Division, Cambridge, MA; Marks Polarized Corporation, Deer Park, NY, Hoya Optics, Inc., Fremont, CA. One last note on mounting filters: recessing displays and bezel assemblies is an inexpensive way to provide a shading effect in overhead lighting situations. Several Bezel manufacturers are: R.M.F. Products, Batavia, IL; Nobex Components, Griffith Plastic Corp., Burlingame, CA; Photo Chemical Products of California, Santa Monica, CA; I.E.E.Atlas, Van Nuys, CA. Microprocessor Interface The microprocessor interface is through the serial port, SPI port or one out of eight data bits on the eight bit parallel port and also control lines SDCLK and LOAD. Power Up Sequence Upon power up display will come on at random. Thus the display should be reset at power-up. The reset will set the Address Register to Digit 0, User RAM is set to 0 (display blank) the Control Word is set to 0 (100% brightness) and the internal counters are reset VCC 18 VCC VCC 40 10 XTAL2 RXD TXD 11 19 XTAL1 U1 8031 P3.7 17 9 RST P3.3 13 15 SDCLK GND 13 LD DATA ID VCC 10 RST CLKSEL 21 19 GND CLK I/O 8 2 14 22 µf TAN + .01 µf P3.4 14 Figure 10. Display Interface to Siemens/Intel 8031 Microprocessor (using serial port in mode 0) SCF5740/2/4 2–209 VCC VCC 40 P3.0 10 18 XTAL2 P3.1 11 P3.6 16 P0.0 19 XTAL1 15 SDCLK GND 13 LD DATA 39 ID U1 8031 VCC 22 µF TAN + 14 VCC 10 19 RST CLKSEL 21 2 GND CLK I/O 8 1 RST 9 P1.0 .01 µF 20 Figure 11. Display Interface to Siemens/Intel 8031 Microprocessor (using one bit of parallel port as serial port) VCC VCC 38 40 OSC1 39 OSC2 PA0 PA1 SCLK MOSI 15 SDCLK GND 13 LD DATA 11 10 33 32 ID VCC 10 CS 21 19 RST 2 GND CLK I/O 8 U1 68HC05C4 VCC 14 22 µF TAN + .01 µF 1 RST 9 PA2 20 Figure 12. Display Interface with Motoroal 68HC05C4 Microprocessor (using SPI Port) RST VCC RST CLK I/O CLK SEL Intelligent Display DATA SDCLK LOAD 14 more displays in between RST CLK I/O CLK SEL Intelligent Display DATA SDCLK LOAD DATA SDCLK A0 A1 A2 A3 0 Chip Address Decoder 15 LD CE Address Decode 1–14 Figure 13. Cascading Multiple Displays Multiple displays can be cascaded using the CLK SEL and CLK I/O pins (Figure 13). The display designated as the MasterClock source should have its CLK SEL pin tied high and the slaves should have their CLK SEL pins tied low. All CLK I/O pins should be tied together. One display CLK I/O can drive 15 slave CLK I/Os. Use RST to synchronize all display counters. SCF5740/2/4 2–210 Loading Data into the Display Use following procedure to load data into the display: 1.Power up the display. 2. Bring RST low (600 ns duration minimum) to clear the Multiplex Counter, Address Register, Control Word Register, User Ram and Data Register. The display will be blank. Display brightness is set to 100%. 3. If a different brightness is desired, load the proper brightness opcode into the Control Word Register. 4. Load the Digit Address into the display. 5. Load display row and column data for the selected digit. 6. Repeat steps 4 and 5 for all digits. Data Contents for the Word “ABCD” Step D 7 D 6 D 5 D 4 D 3 D 2 D D 1 0 Function A B (optional) 1 1 1 1 0 1 0 0 0 0 0 0 0 0 0 0 CLEAR 100% BRIGHTNESS 1 2 3 4 5 6 7 8 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 0 0 1 0 1 0 0 0 0 1 0 0 1 0 0 0 0 0 1 0 1 0 0 0 0 0 0 1 1 1 1 1 DIGIT D0 SELECT ROW 0 (Α) ROW 1 Α) ROW 2 (Α) ROW 3 (Α) ROW 4 (Α) ROW 5 (A) ROW 6 (A) 9 10 11 12 13 14 15 16 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 0 1 0 0 1 0 0 1 0 1 0 0 1 0 0 1 0 1 0 0 1 0 0 1 1 1 1 1 0 1 1 1 DIGIT D1 SELECT ROW 0 (B) ROW 1 (B) ROW 2 (B) ROW 3 (B) ROW 4 (B) ROW 5 (B) ROW 6 (B) 17 18 19 20 21 22 23 24 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 1 0 0 0 1 0 0 1 0 0 0 0 0 1 1 1 0 0 0 0 0 1 0 1 0 0 0 0 0 1 DIGIT D2 SELECT ROW 0 (C) ROW 1 (C) ROW 2 (C) ROW 3 (C) ROW 4 (C) ROW 5 (C) ROW 6 (C) 25 26 27 28 29 30 31 32 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 0 1 0 0 0 0 0 1 0 1 0 0 0 0 0 1 1 1 0 0 0 0 0 1 1 0 1 1 1 1 1 0 DIGIT D3 SELECT ROW 0 (D) ROW 1 (D) ROW 2 (D) ROW 3 (D) ROW 4 (D) ROW 5 (D) ROW 6 (D) SCF5740/2/4 2–211