Communication ICs Panel interface BU8310AK / BU8311KS / BU8313K The BU8310AK, BU8311KS, and BU8313K are large-scale integrated circuits for telephones, which enable a serial input / output interface between the key input required for telephone panel boards and LED control functions. They reduce the number of wiring harnesses needed between the main board in the telephone and the panel board, and take some of the processing load off the main CPU. Applications Telephones and cordless telephones Features 1) Keypad matrix interface 1 Key input is output as 16-bit serial data. 2 Internal chattering prevention circuit built into the key input circuit. 2) LED interface 1 LED control commands input as 16-bit serial data. 2 Bits with a pattern generator and pattern register can be assigned three independent flashing patterns in addition to being lighted or off. 3 Power consumption can be reduced using RST pin input. 4 LED on and off control can be initiated using ENA pin input or by commands setting all LEDs valid or invalid. 277 Communication ICs Block diagram 278 BU8310AK / BU8311KS / BU8313K Communication ICs BU8310AK / BU8311KS / BU8313K 279 Communication ICs FAbsolute maximum ratings (Ta = 25_C) FRecommended operating conditions FPin descriptions 280 BU8310AK / BU8311KS / BU8313K Communication ICs BU8310AK / BU8311KS / BU8313K Input / output circuits 281 Communication ICs BU8310AK / BU8311KS / BU8313K FElectrical characteristics DC characteristics (unless otherwise noted,Ta = 25_C, VDD = 3 5V) AC characteristics (unless otherwise noted, Ta = 25_C, VDD = 3 5V) 282 Communication ICs BU8310AK / BU8311KS / BU8313K Serial data output timing Serial data input timing 283 Communication ICs BU8310AK / BU8311KS / BU8313K Data formats (Serial data is input and output with the MSB coming first.) (1) Reading key data (2) Data register write command (3) Pattern register write command (4) All LEDs valid command (5) All LEDs invalid command 284 Communication ICs BU8310AK / BU8311KS / BU8313K (6) Register reset command Entering data settings (1) Setting operands (2) Setting the blink cycle Driver internal equivalent circuit (for 1 bit) 285 Communication ICs Recommended method for inputting / outputting data (1) Serial output of key data (2) Serial input of LED control commands 286 BU8310AK / BU8311KS / BU8313K Communication ICs Operation notes (1) Serial output of key data when several keys are pressed at the same is as shown below. BU8310AK / BU8311KS / BU8313K (3) When the power supply is turned on, the internal registers should be reset using either RST pin input or the register reset command. (4) If the RST pin is set to LOW or the register reset command is executed while data is being output, the SDO output logic is not reset. (5) If the D, P, and Q registers are rewritten, all eight bits should be written, and not just the pertinent bits. The key data when 32 and 43 are pressed at the same time will be the same as the key data when 33 and 42 are pressed at the same time. (2) Pressing different keys When a different key is pressed from the one already pressed, KD is turned temporarily to provide notification of the change. (6) Operation states in response to RST, KSCN and ENA pin input 287 Communication ICs External dimensions (Units: mm) 288 BU8310AK / BU8311KS / BU8313K