Motorola APX 7000 Basic Service Manual page 44

Sec 1: 3-12 Basic Theory of Operation: Controller Section
The power and most clocks to the controller devices are provided by the MAKO IC and external
switching and linear regulators on board. A Complex Programmable Logic Array (CPLD) IC divides
the 24.576 Mhz clock from MAKO to source OMAP's 32 kHz Real Time Clock, and MACE's 4 Mhz
main clock. OMAP's main clock is supplied externally from an on board 12 Mhz crystal.
The radio has two internal microphones and two internal speakers, as well as available microphone
and speaker connections for external accessories. The main external speaker is located opposite to
the main display and keypad of the radio. It can deliver a rated power of 1W on a ~4 Ohms speaker,
while the smaller "data" speaker can only deliver 0.5 W of power on a load of 16 Ohms. Both internal
and external microphones use the CODEC's AD to deliver digital audio samples to the DSP
controller. The main speaker is driven by the class D PA on the expansion board, while the data and
external speakers are driven by the AB type PA on MAKO. Both speaker paths use the CODEC for
volume control and to convert audio from digital to analog.
The user interface block consists of a top and main or "data side" display, a keypad, top controls and
the accessory side connector. The side connector (Universal Connector) provides audio, USB,
RS232 and RF communication for accessories. All signals to and from the connector go through the
internal expansion board before reaching the microcontroller and other devices on the main board.
The radio also has an expansion bay for a Micro SD memory card, a Global Positioning System
(GPS) interface, and an option slot for radio feature upgrades. The memory card can be inserted on
the bay near the battery connector of the radio. The option slot of the radio is available internally to
the radio, and it is not hot swappable by the user. The option slot is available through a connector
directly linked to the main controller board.