KBDSER56 ABCIRCUITS | Alldatasheet

Document overview

  • Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
  • PDF pages: 7

Technical content

Features

  • Asynchronous serial output.
  • Fully encodes a key switch array . (up to 7 x 8)
  • No external parts required .
  • Low power consumption 2 mA typical.
  • Supply voltage 2.4 to 5 .25 volts.
  • All timing internally generated .
  • 2 Key rollover.
  • On chip row input resistors .
  • Internal key bounce elimination .
  • TTL and CMOS compatible outputs .
  • Part is in full production .
  • SOIC 20 Pin Packag e.
  • ROHS Compliant
  • Low EMI

Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Part Number KBDSER56 January 2013 Page 2 of 7 Example Circuits RS232 20 21 22 28 29 2A 30 31 32 38 39 3A 23 24 25 26 27 2B 2C 2D 2E 2F 33 34 35 36 37 3B 3C 3D 3E 3F 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 KEYPAD VCC GND KBDSER56 COLX1 NC COLX3 COLX5 COLX7 NC ROWY8 ROWY6 ROWY4 ROWY2 SOUT COLX6 COLX2 VSS ROWY5 COLX4 ROWY1 ROWY7 VDD ROWY3 U2= MAX232 FOR 5V RS232 U2= MAX3232 FOR 3V RS232

56 KEY RS232 KEYBOARD

-DO/-RI DO / RI RO DI -RE DE VCC KBDSER56 COLX1 NC COLX3 COLX5 COLX7 NC ROWY8 ROWY6 ROWY4 ROWY2 SOUT COLX6 COLX2 VSS ROWY5 COLX4 ROWY1 ROWY7 VDD ROWY3 U2 75176 FOR 5V 20 21 22 28 29 2A 30 31 32 38 39 3A 23 24 25 26 27 2B 2C 2D 2E 2F 33 34 35 36 37 3B 3C 3D 3E 3F 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 KEYPAD VCC RS485 OUT U2 MAX3485 FOR 3.3V VCC

56 KEY RS-485 KEYBOARD

Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Part Number KBDSER56 January 2013 Page 3 of 7 KBDSER56 COLX1 NC COLX3 COLX5 COLX7 NC ROWY8 ROWY6 ROWY4 ROWY2 SOUT COLX6 COLX2 VSS ROWY5 COLX4 ROWY1 ROWY7 VDD ROWY3 +3.3 ETHERNET LANTRONIX XPORT GND +3.3 -POR OUT IN CP1 CP2 CP3 20 21 22 28 29 2A 30 31 32 38 39 3A 23 24 25 26 27 2B 2C 2D 2E 2F 33 34 35 36 37 3B 3C 3D 3E 3F 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 KEYPAD

56 KEY ETHERNET KEYBOARD

+3.3 Connection Diagram KBDSER56 COLX1 NC COLX3 COLX5 COLX7 NC ROWY8 ROWY6 ROWY4 ROWY2 SOUT COLX6 COLX2 VSS ROWY5 COLX4 ROWY1 ROWY7 VDD ROWY3 Pin Description Pin # Description Pin # Description

1 Row Y8 20 VDD

2 Row Y6 19 Row Y7

3 Row Y4 18 Row Y5

4 Row Y2 17 Row Y3

5 NC 16 Row Y1

6 SOUT 15 NC

7 Col X6 14 Col X7

8 Col X4 13 Col X5

9 Col X2 12 Col X3

10 VSS 21 Col X1

Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Part Number KBDSER56 January 2013 Page 4 of 7 Col X1 – Col X7 These pins are open drain column driver outputs to the key matrix . Row Y1 – Row Y8 These pins are the row inputs from the key matrix . These inputs have 5.6K (nominal) pull up resistors on chip. SOUT This is the serial output pin. It may be tied directly to the UART receiver input of your UART or microprocessor; to a RS -232 driver such as the MAX232 ; a standard RS485 driver such as the 75176 or an Ethernet interface such as the Lantronix Xport. This pin is high in the idle state, the output format is 8 bits, 1 stop, no parity at 9600 BPS. Other output formats and baud rates are available, please contact the factory for information. VSS Connect to system ground. VDD Connect to supply voltage of 2.4 to 5 volts . A .1 uF decoupling capacitor to ground is recommended. NOTES: Make no connection to the NC pins . Pins 5 and 15 must be left unconnected . Truth Table The ASCII output codes of the KBDSER56 were chosen to make it easier to design, diagnose and translate codes easier. The ASCII outputs can be seen using any terminal program such as Hyperterm, and easily translated by subtracting 32 (020h) , and then using the remainder as an offset into a translation table. Custom output codes are available, consult the factory for information. ROWY1 ROWY2 ROWY3 ROWY4 ROWY5 ROWY6 ROWY7 ROWY8 ASCII OUT HEX COLX1 X SPACE 20 COLX1 X ! 21 COLX1 X “ 22 COLX1 X # 23 COLX1 X $ 24 COLX1 X % 25 COLX1 X & 26 COLX1 X ‘ 27 COLX2 X ( 28 COLX2 X ) 29 COLX2 X * 2A COLX2 X + 2B COLX2 X , 2C COLX2 X - 2D COLX2 X . 2E COLX2 X / 2F COLX3 X 0 30 COLX3 X 1 31 COLX3 X 2 32 COLX3 X 3 33 COLX3 X 4 34 COLX3 X 5 35 COLX3 X 6 36

Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Part Number KBDSER56 January 2013 Page 5 of 7 COLX3 X 7 37 COLX4 X 8 38 COLX4 X 9 39 COLX4 X : 3A COLX4 X ; 3B COLX4 X < 3C COLX4 X = 3D COLX4 X > 3E COLX4 X ? 3F COLX5 X @ 40 COLX5 X A 41 COLX5 X B 42 COLX5 X C 43 COLX5 X D 44 COLX5 X E 45 COLX5 X F 46 COLX5 X G 47 COLX6 X H 48 COLX6 X I 49 COLX6 X J 4A COLX6 X K 4B COLX6 X L 4C COLX6 X M 4D COLX6 X N 4E COLX6 X O 4F COLX7 X P 50 COLX7 X Q 51 COLX7 X R 52 COLX7 X S 53 COLX7 X T 54 COLX7 X U 55 COLX7 X V 56 COLX7 X W 57 Absolute Maximum Ratings Symbol Description Min Typical Max Units Notes Tstg Storage Temperature -55 25 +100 ºC Ta Operating Temperature -40 +85 ºC Vdd Vdd - Vss Voltage -0.5 +6.0 V Vio Input Voltage Vss - 0.5 Vdd +0.5 V Imio Maximum current into any pin -25 +50 mA ESD Electrostatic Discharge Voltage 2000 V Human Body Model ESD LU Latch up current 200 mA

Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Part Number KBDSER56 January 2013 Page 6 of 7 Symbol Description Min Typical Max Units Notes Vdd Supply Voltage 2.4 5.25 V Idd Supply Current 2 8 mA Vdd = 5V Voh High Output Level Vdd - 1.0 V Ioh=10 mA Vol Low Output Voltage 0.75 V Iol=25 mA Vih Input High Level 2.1 V Vil Input Low Level 0.8 V Ioh High Level Source Current 10 mA Iol Low Level Sink Current 25 mA Cio Capacitive load 3.5 10 pF Iil Input leakage 1 nA Rpu Pull Up Resistors On Row Inputs 4 5.6 8 k? Theory Of Operation The KBDSER56 IC is a custom programmed microprocessor designed to encode keyboards and provide a serial output. The open drain COLX pins are pulsed low one at a time, and the ROWY pins are sampled to check for key switch closures . If a key is detected, scanning stops until the key is released. The pressed key is encoded to ASCII and transmitted in standard asynchronous format on the SOUT key. The key is transmitted using 8 data bits, 1 stop bit and no parity. Baud rate is 9600 BPS. When the key is released scanning continues.

Turning Ideas Into Reality ABCircuits www.abcircuits.com POB 123 New Hill NC 27562 (919) 290-7104 Part Number KBDSER56 January 2013 Page 7 of 7 Physical Dimensions Design Services Available We can quickly turn your idea into a chip, a pc board, or a finished product. Contact us with your needs and specifications.