Keyboard Assembly; Main Pcb; Tgc_Pcb - GE LOGIQ A3 Basic Service Manual

GE H
EALTHCARE
D 5213326-100, R
IRECTION
5-2-6

Keyboard Assembly

5-2-6-1

Main PCB

This board will be mounted on to the rear of keyboard. This will be a 4 LAYER FAB. (Complete
Electronics) This houses the controller, CPLD/FPGA & other logic circuits. The key code data & TGC
ADC value is sent to MST using asynchronous serial interface. Track ball movement and trackball
switch data to be sent via PS/2 interface.
The following will be major functional requirements of the keyboard PCB.
1.) This keyboard shall provide interface to scan 16 x 8 key matrix type alphanumeric keyboard. This
PCB must have connectors, which interfaces to 24-pin FPC cable and LED's from alphanumeric
keyboard.
2.) The keyboard shall have scan matrix for Ultrasound keys.
3.) Backlighting arrangement –Individual Ultrasound keys will have some sets of LED's (4 nos) &
Individual LED with in the set cannot be controllable. The LED's brightness will be controlled by the
PWA (Pulse Width Adjustment) or similar means. The LED ON & OFF period will be controlled
based on the "Hex" value set from the Host side. LED should be of High Luminescence type and
shall consume less power.
4.) Encoder interface – The phase quadrature output of encoder will be connected to CPLD or micro
controller interrupt pin. The de bouncing of the signal needs to be done & 4or 8-bit counter will be
updated depending on the direction of rotation. The encoder switches are connected to the
ultrasound scan matrix.
5.) TGC PCB Interface – TGC analog input is connected to a connector on keyboard PCB. These
signals will be connected to micro controller port with ADC built in. Each TGC pot has different ID
& equivalent digital value is sent back toHOST using asynchronous serial interface.Power On/Off
switch - This key will be part of ultrasound key switch matrix. Bicolor LED shall be provided and will
be driven from the host for indicating the status of Power.
5-2-6-2

TGC_PCB

This PCB houses 6 Potentiometer encoders. This gets connected to keyboard PCB through cable
assembly.
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Approv e d Docu m ent - 5213326-100TPH_r3.pdf Page 113 of 252
3
EVISION
Section 5-2 - Block Diagrams and Theory
LOGIQ™ A3 S M
ERVICE ANUAL