THEORY OF OPERATION (ENHANCED CONTROL HEADS) 4.2 - 1
CHAPTER 4.2
THEORY OF OPERATION (ENHANCED CONTROL
HEADS)
This chapter contains the descriptions of the different configurations of the Enhanced Control Head:
• Enhanced Control Head in Dash Mount configuration
• Enhanced Control Head in Remote Mount configuration
Remote Back Head
Data Expansion Head Enhanced
Remote Head Enhanced
• Enhanced Control Head in Motorcycle configuration
Enhanced Control Head in Dash Mount configuration
The Enhanced Control Head in dash mount configuration consists of the main board, the liquid crys-
tal display (LCD) module, the keypad board, the keypad, the rotary and push button, the EMER-
GENCY button, the GCAI accessory connector, the 3-colour status LED and the housing.
The display module contains a colour 2.8" VGA TFT display.
The 3 colour status LED informs the user about the radio status
The functions of the Enhanced Control Head are driven by the OMAP1621 microcontroller from
Texas instruments.
Power Supplies
The power supply to the Enhanced Control Head is taken from the host radio's FLT A+ voltage via
connector J101 pin 3. It is used to power up the Enhanced Control Head.
The regulator U513 provides an unswitched stabilized 5V to constantly power some circuits.
The switching regulator U501 produces 5V when the system is switched ON. The output voltage of
U501 feeds the following regulators U503, U504 and U505. Furthermore the VCC_5 voltage is used
to supply the keypad backlight.
The boost regulator U503 generates 23V for the display backlight.
The reset IC U502 enables the regulator U503 when the output voltage of U501 exceeds 2.8V. U503
produces the 1.5V core voltage for the OMAP microcontroller.
Only when the 1.5V is stable, the regulator U504 is enabled and generates 3.3V for USB and as
input voltage for the two regulators U506 and U507. U507 provides 1.8V to the memory block of the
OMAP and to the memories themselves.
U506 generates 2.8V for the I/O section of the OMAP.
The 2.8V also release the clear input of the D-Flip Flop U509. At the same time the crystal oscillator
U515, Y501, R520 - R523 and C530 - C532 starts oscillating at 32.768 kHz and the binary counter
6866539D31.book Page 1 Tuesday, March 20, 2007 6:32 PM
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