6815854H01-A June 15, 2005
Theory of Operation: Power Management 3-3
The OMAP IC also requires a 32.768 kHz square-wave clock, provided at the P13 pin. This clock is
generated by a 32.768 kHz crystal (Y1000), with supporting circuitry for oscillation. This clock is
utilized only for the OMAP IC, and is used for reset capability and other OMAP IC functions. Note
that the rise/fall time of this clock is optimum at 20ns or less.
Figure 3-3. Control Head Controller Block
NOTE: The controller section (OMAP, Flash and SDRAM) are highly susceptible to ESD and
moisture damage. Extreme care is advised when handling or servicing the control head
board.
3.4 Power Management
XTL1500 utilizes a smart power control system in which the 8-bit ATTiny13 microcontroller (U2303)
processes all the power up, power down, and resets of the radio. A series of commands is issued
from the Patriot IC to the ATTiny13 through BUS_PWR_OUT while the OMAP IC does that through
B+_CTRL. All resets and radio power up/down is then outputted from the ATTiny13 through 5V_EN.
The sub-sections to follow will describe in detail the power management design of the radio.
32.768 kHz crystal
oscillator circuit
(2.8V p-p sine wave)
1.55V
12 MHz crystal
(1.5V p-p sine wave)
TPS65012 PWR MGT IC (I2C)
Camera Interface (SoSSI)
Volume Pot A/D converter (SPI)
MUX CTRL pins, ATTiny13, LEDs,
Accy. Output signals, VIPOUTs.
Frequency knob, Accy. input signals,
Reset signals, Power control signals
SSI link to transceiver
1.88V
2.8V
3.3V
ARM
CORE
EIM
I/Os,
UART,
USB
OMAP
2MB
FLASH
8MB
SDRAM
USB UART
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