STM86312 1/4 TO 1/11-DUTY VFD CONTROLLER/DRIVER ■ ■ ■ ■ ■ ■ ■ ■ MANY DISPLAY MODES (11 SEGMENTS & 11 DIGITS TO 16 SEGMENTS & 4 DIGITS) KEY SCANNING (6 x 4 MATRIX) DIMMING CIRCUIT (EIGHT STEPS) HIGH-VOLTAGE OUTPUT (VDD – 35V MAX) LED PORTS (4 CHS, 20mA MAX) GENERAL PURPOSE INPUT PORT (4 bits) NO EXTERNAL RESISTOR NECESSARY FOR DRIVER OUTPUT (P-CH OPEN DRAIN + PULL DOWN RESISTOR OUTPUT) SERIAL INTERFACE (CLK, STB, DIN, DOUT) DESCRIPTION The STM86312 is a VFD (Vacuum Fluorescent Display) controller/driver that is driven on a 1/4 to 1/11-duty factor. It consists of 11-segments output lines, 6 grid output lines, 5 segments/grid output drive lines, a display memory, a control circuit, and a key scan circuit. Serial data are input to the STM86312 through a three-line serial interface. PQFP44 This VFD controller/driver is ideal as a peripheral device for a single-chip microcomputer. ORDERING CODES Type Temperature Range Package Comments STM86312 -40 to 85 °C PQFP44 250 parts per Reel May 2004 Rev. 1 1/16 STM86312 Figure 1: Block Diagram Figure 2: Pin Configuration (TOP VIEW) 2/16 STM86312 Table 1: Pin Description PlN N° SYMBOL 1, 2, 3, 4 SW1, SW2, SW3, SW4 5 DOUT 6 DIN 8 CLK 9 STB 10, 11, 12, 13 14, 38 15, 16, 17, 18, 19, 20 21, 22, 23, 24, 25 26, 28, 29, 30, 31 32, 33, 34, 35, 36, 37 39, 40, 41, 42 KEY1, KEY2, KEY3, KEY4 VDD SEG1/KS1 to SEG6/KS6 SEG7 to SEG11 NAME AND FUNCTION General-purpose switch inputs. Output serial data at falling edge of the shift clock, starting from lower bit. This is N-ch open-drain output pin. Input serial data at rising edge of the shift clock, starting from lower bit. Reads serial data at rising edge, and outputs data at falling edge. Initializes serial interface at rising or falling edge to make STM86312 waiting for reception of command. Data input after STB has fallen are processed as a command. While command data are processed, current processing is stopped, and the serial interface is initialized. While STB is high, CLK is ignored. Input data to these pins are latched at end of the display cycle. 5V ± 10%. Segment output pins (Dual function as key source). Segment output pins. SEG12/GRID11 to These pins are selectable for segment or grid driving. SEG16/GRID7 Grid output pins. GRID1 to GRID6 LED1 to LED4 VSS CMOS outputs. +20 mA max. Connect this pin to system GND. 27 VEE Pull-down level. VDD - 35V max. 44 OSC Connect to an external resistor. 7, 43 Table 2: Absolute Maximum Ratings (TA = 25°C, VSS = 0V) Symbol Value Unit VDD Logic Supply Voltage -0.5 to 7 V VEE Driver Supply Voltage VDD+0.5 to VDD-40 V Logic Input Voltage -0.5 to VDD+0.5 VEE-0.5 to VDD+0.5 V VI Parameter VO2 VFD Driver Output Voltage IO1 LED Driver Output Current 25 mA VFD Driver Output Current -40 (Grid) -15 (Segment) mA -40 to 85 °C IO2 TA Operating Ambient Temperature V Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. Table 3: Thermal Data Symbol RTj-c Parameter Thermal Resistance Junction-Case Value Unit 56 °C/W 3/16 STM86312 Table 4: Recommended Operating Conditions Symbol Parameter Min TYP Max Unit 4.5 5 5.5 V VDD Logic Supply Voltage VIH High Level Input Voltage 0.7xVDD VDD V VIL Low Level Input Voltage 0 0.3xVDD V VEE Driver Supply Voltage 0 VDD-35 V Maximum power consumption PMAX = VFD driver dissipation + RL dissipation + LED driver dissipation + dynamic power consumption. Where segment current = 3 mA, grid current = 15 mA, and LED current = 20 mA, VFD driver dissipation = number of segments x 6 + number of grids/(number of grids + 1) x 30 (mW) RL dissipation = (VDD - VEE)2/50 x (segment + 1) (mW) LED driver dissipation = number of LEDs x 20 (mW) Dynamic power consumption = VDD x 5 (mW) Example Where VEE = -25 V, VDD = 5 V, and in 16-segment and 6-digit modes, VFD driver dissipation = 16 x 6 + 6/7 x 30 = 122 RL dissipation = 302/50 x 17 = 306 LED driver dissipation = 4 x 20 = 80 Dynamic power consumption = 5 x 5 = 25 Total 553 mW. Table 5: Electrical Characteristics (VDD = 4.5 to 5.5V, VSS = 0V, VEE = VDD - 35V, TA = -20 to 70°C, unless otherwise noted. Typical values are at TA = 25°C) Value Symbol Parameter Test Conditions Unit Min. VOH1 High Level Output Voltage LED1-LED4, IOH1=-1mA VOL1 Low Level Output Voltage LED1-LED4, IOL1=20mA VOL2 Low Level Output Voltage DOUT, IOL2 = 4mA Typ. Max. 0.9VDD V 1 V 0.4 V IOH21 High Level Output Current VO = VDD - 2V, Seg1 to Seg11 -3 mA IOH22 High Level Output Current -15 mA IOLEAK Driver Leakage Current VO = VDD - 2V, Grid1 to Grid6, Seg12/Grid11 to Seg16/Grid7 VO = VDD - 35V, driver off Output Pull-Down Resistor Driver Output 50 Input Current VI = VDD or VSS RL II VIH High Level Input Voltage VIL Low Level Input Voltage µA 150 kΩ ±1 µA 0.7VDD VHYS Hysteresis Voltage CLK, DIN, STB IDDdyn Dynamic Current Consumption Under no load, display off 4/16 100 -10 V 0.3VDD V 5 mA 0.35 V STM86312 Table 6: Switching Characteristics (VDD = 4.5 to 5.5V, VSS = 0V, VEE = VDD - 35V, TA = -20 to 70°C, unless otherwise noted. Typical values are at TA = 25°C) Value Symbol Parameter Test Conditions Unit Min. Propagation Delay CLK → DOUT RL = 10 kΩ, CL = 15 pF Rise Time CL = 300 pF tTHZ Fall Time Grid1 to Grid6, Seg12/ Grid11 to Seg16/Grid7 CL = 300 pF, Segn, Gridn fMAX Maximum Clock Frequency Duty = 50% tPLZ tPZL tTZH1 tTZH2 Typ. 300 ns 100 Seg1 to Seg11 2 µs 0.5 120 1 µs MHz Input Capacitance CI Max. 15 pF Table 7: Timing Characteristics (VDD = 4.5 to 5.5V, TA = -20 to 70°C, unless otherwise noted. Typical values are at TA = 25°C) Value Symbol Parameter Test Conditions Unit Min. PWCLK Clock Pulse Width PWSTB Strobe Pulse Width tSETUP Data Setup Time tHOLD Data Hold Time Typ. 400 Max. ns 1 µs 100 ns 100 ns tCLK-STB Clock-Strobe Time CLK ↑→ STB↑ 1 µs Wait Time (Note 1) CLK ↑→ CLK↓ 1 µs tWAIT NOTE 1: Refer to page Serial Communication Format. DISPLAY RAM ADDRESS AND DISPLAY MODE The display RAM stores the data transmitted from an external device to the STM86312 through the serial interface; addresses are as follows, in 8-bits unit: Seg1 Seg4 Seg8 Seg12 00 HL 00 HU 01 HL 02 HL 02 HU 03 HL 04 HL 04 HU 05 HL 06 HL 06 HU 07 HL 08 HL 08 HU 09 HL 0A HL 0A HU 0C HL 0E HL 10 HL 10 HU 11 HL 12 HL 12 HU 13 HL 14 HL 14 HU 15 HL b0 DIG1 05 HU 07 HU DIG3 DIG5 0B HL 09 HU 0B HU 0C HU 0D HL 0D HU DIG7 0E HU 0F HL 0F HU 11 HU DIG8 13 HU 15 HU DIG10 b3 b4 XX HL Seg16 01 HU 03 HU DIG2 DIG4 DIG6 DIG9 DIG11 b7 XX HU "0" in memory means VEE on output; "1" in memory means VDD on output. 5/16 STM86312 Figure 3: Key Matrix And Key-input Data Storage Ram The key matrix is of 6 x 4 configuration, as shown below The data of each key are stored as illustrated below, and are read by the appropriate read command, starting from the least significant bit KEY1 KEY4 KEY1 Seg1/KS1 Seg3/KS3 Seg5/KS5 KEY4 Seg2/KS2 Seg4KS4 Seg6/KS6 b0 b3 b4 ↓ b7 LED PORT Data are written to the LED port by a write command, starting from the least significant bit of the port. When a bit of this port is 0, the corresponding LED lights; when the bit is 1, the LED goes off. The data of bits 5 through 8 are ignored. MSB - - - - b3 b2 b1 LSB b0 LED1 LED2 LED3 LED4 Don’t Care On power application, all the LEDs remain dark. 6/16 STM86312 SW DATA The SW data are read by the appropriate read command, starting from the least significant bit. Bits 5 through 8 of the SW data are 0. MSB 0 0 0 0 b3 b2 b1 LSB b0 SW1 SW2 SW3 SW4 COMMANDS A command sets the display mode and status of the VFD driver. The first 1 byte input to the STM86312 through the DIN pin after the STB pin has fallen is regarded as a command. If STB is set high while commands/data are transmitted, serial communication is initialized, and the commands/data being transmitted are invalid (however, the commands/data already transmitted remain valid). (1) DISPLAY MODE SETTING COMMAND This command initializes the STM86312 and selects the number of segments and number of grids (1/4 to 1/11 duty, 11 segments to 16 segments). When this command is executed, display is forcibly turned off, and key scanning is also stopped. To resume display, the display ON command must be executed. If the same mode is selected, however, nothing is performed. MSB 0 0 - - - b2 b1 LSB b0 DISPLAY MODE SETTING 000 : 4 digits, 16 segments 001 : 5 digits, 16 segments 010 : 6 digits, 16 segments 011 : 7 digits, 15 segments 100 : 8 digits, 14 segments 101 : 9 digits, 13 segments 110 : 10 digits, 12 segments 111 : 11 digits, 11 segments Don’t Care On power application, the 11-digit 11-segment mode is selected. 7/16 STM86312 (2) DATA SETTING COMMAND This command sets data write and data read modes. MSB 0 1 - - 0 b2 b1 LSB b0 DATA WRITE AND READ MODE SETTING 00 : Write data to display memory 01 : Write data to LED port 10 : Read key data 11 : Read SW data ADDRESS INCREMENT MODE SETTING (DISPLAY MEMORY) 0= Increments address after data has been written 1= Fixed address Don’t Care On power application, the normal operation mode and address increment mode are set. Do not use STM86312 in test mode. (3) ADDRESS SETTING COMMAND This command sets an address of the display memory MSB 1 1 - b4 b3 b2 b1 LSB b0 Address (00H-15H) Don’t Care If address 16H or higher is set, the data are ignored, until a correct address is set. On power application, the address is set to 00H. (4) DISPLAY CONTROL COMMAND MSB 1 0 - - b3 b2 b1 LSB b0 DISPLAY MODE SETTING 000 : Set Pulse Width to 1/16 001 : Set Pulse Width to 2/16 010 : Set Pulse Width to 4/16 011 : Set Pulse Width to 10/16 100 : Set Pulse Width to 11/16 101 : Set Pulse Width to 12/16 110 : Set Pulse Width to 13/16 111 : Set Pulse Width to 14/16 TURNS ON/OFF DISPLAY 0= Display OFF (Key Scan Continues *) 1= Display ON Don’t Care On power application, the 1/16-pulse width is set and the display is turned off. *: On power application, key scanning is stopped. 8/16 STM86312 Figure 4: Key Scanning And Display Timing * The value can be modified by trimmering ROSC. One cycle of key scanning consists of one frame, and data of 6 x 4 matrices are stored in RAM. SERIAL COMMUNICATION FORMAT Figure 5: Reception (command/data write) 9/16 STM86312 Figure 6: Transmission (data read) Because the DOUT pin is an N-ch open-drain output pin, be sure to connect an external pull-up resistor to this pin (1 kΩ to 10 kΩ). *: When data are read, a wait time tWAIT of 1µs is necessary within the rising edge of the eighth clock that has set the command and the falling one of the first clock that has read the data. Figure 7: Switching Characteristics Waveform 10/16 STM86312 APPLICATION Figure 8: Updating display memory by incrementing address Command 1: sets display mode Command 2: sets data Command 3: sets address Data 1 to n: transfers display data (22 bytes max.) Command 4: controls display Figure 9: Updating specific address Command 1: sets data Command 2: sets address Data: display data 11/16 STM86312 Figure 10: Application Circuit Note: ROSC = 47kΩ for oscillator resistor R1=1~10 kΩ for external pull-high resistor R2~R5 = 750Ω~1.2 kΩ R6~R9 = 10kΩ for external pull-low resistor D1~D6 = 1N4001 Ef = Filament voltage for VFD. 12/16 STM86312 PQFP44 MECHANICAL DATA mm. inch DIM. MIN. TYP MAX. MIN. TYP. MAX. A 2.45 0.096 A1 0.25 0.010 A2 1.80 b c 2.00 2.20 0.071 0.079 0.29 0.45 0.011 0.018 0.11 0.23 0.004 0.009 D 13.2 0.520 D1 10.00 0.394 D3 8.00 0.315 E 13.2 0.520 E1 10.00 0.394 E3 8.00 0.315 e 0.80 0.031 L 0.73 L1 K 0.88 1.03 0.029 1.6 0° 3.5° 0.035 0.087 0.041 0.063 7° 0° 3.5° 7° 0076922/D 13/16 STM86312 Tape & Reel PQFP44 MECHANICAL DATA mm. inch DIM. MIN. A MAX. MIN. 330 13.2 TYP. MAX. 12.992 C 12.8 D 20.2 0.795 N 60 2.362 T 14/16 TYP 0.504 30.4 0.519 1.196 Ao 12.25 12.45 0482 0.490 Bo 12.25 12.45 0482 0.490 Ko 2.1 2.3 0.083 0.091 Po 3.9 4.1 0.153 0.161 P 15.9 16.1 0.626 0.639 STM86312 Table 8: Revision History Date Revision 27-May-2004 1 Description of Changes First Release 15/16 STM86312 Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. 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