LG CU920 Manual page 54

3. TECHNICAL BRIEF
3.7.15 Mode Select and JTAG Interfaces
The mode pins to the MSM6281 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 MSM6281 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.
3.7.16 General-Purpose Input/Output Interface
The MSM6281 device has general-purpose bidirectional input/output pins. 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.
3.7.17 UART
The MSM6281 device employs three UARTs. UART1 has dedicated pins while UART2 and UART3
share multiplexed pins.
■ UART1 for data
■ UART2 (can be used for USIM interface)
■ UART3 for data
3.7.18 USB
The MSM6281 device integrates a universal serial bus (USB) controller that supports both
unidirectional and bidirectional transceiver interfaces. The USB controller acts as a USB peripheral
communicating with the USB host.
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