3. TECHNICAL BRIEF
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3.9.8. Mode Select and JTAG Interfaces
The mode pins to the MSM7227 device determine the overall operating mode of the ASIC. The options under
the control of the mode inputs are Native mode, which is the normal subscriber unit operation, ETM mode,
which enables the built-in trace mode, and test mode for factory testing. The MSM7227 device meets the
intent of the ANSI/IEEE 1149.1A-1993 feature list. The JTAG interface can be used to test digital interconnects
between devices within the mobile station during manufacture.
3.9.9. General-Purpose Input/Output Interface
The MSM7227 IC includes 133 general purpose input/output (GPIO) pins, and each can be configured as a
digital input or digital output. Inputs can be set to have a pull-up, pull-down, keeper, or no-pull. Output drive
strength is also programmable. Software assigns functions to the GPIOs and their configurations are set
accordingly. Some of the GPIO pins have alternate functions supported on them. The alternate functions
include USB interface, additional RAM, ROM, general-purpose chip selects, parallel LCD interface, and a UART
interface. The function of these pins is documented in the various software releases.
3.9.10. UART
The MSM7227 device employs three UARTs. UART1 has dedicated pins while UART2 and UART3 share
multiplexed pins.
-UART1 for Bluetooth
-UART2 for USIM interface
-UART3 for data
.
3.9.11. USB
The MSM7227 IC supports one High Speed USB (HS-USB) USBH port with built-in PHY and one Full Speed
USB-UICC port. The MSM7227 IC supports USB interfaces using two controllers:
-The primary controller is the HS-USB port with an integrated physical layer (PHY). This HSଝ -USB port is
also capable of supporting USB operations at low-speed and full-speed.
-The secondary controller is the FS USB-UICC port, which only supports host mode functionality.
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