
Functional Overview
177
December 2003 Revised March 2005
SPRS231D
Each timer has three possible clock sources:
the 32-kHz clock
the system clock
an external clock source
NOTE:
Three of the eight dual-mode timer PWM outputs are connected at OMAP5912 I/Os. Two of the eight
dual-mode timer input capture are connected at OMAP5912 I/Os. The system clock can come either from
OMAP or directly from the input clock.
Can wake up the system when the clock is configured as 32-kHz through its own interrupt through a
general-purpose timer
3.8.3 Serial Port Interface (SPI)
The serial port interface is a bidirectional, four-line interface dedicated to the transfer of data to and from
external devices offering a four-line serial interface. The four-line interfaces are:
the clock used to shift-in and shift-out data
the device enable
the data input
the data output
This serial port interface is based on a looped shift-register, thus allowing both transmit and receive modes.
It can operate either in master or slave mode, using MPU or DMA control.
In master mode, the SPI provides up to four chip-selects for external devices. In slave mode, the SPI has its
own chip-select.
In master mode, the maximum SPI data rate is the same as the system clock frequency; in slave mode, the
clock of the serial data out is provided by an external device at lower data rate.
3.8.4 Universal Asynchronous Receiver/Transmitter (UART)
The OMAP5912 includes three universal asynchronous receiver/transmitter (UART) peripherals which are
accessible on the DSP public and MPU public peripheral buses. The MPU configures the UART’s owner
processor (MPU or DSP). All three UARTs are standard 16C750-compatible UARTs implementing an
asynchronous transfer protocol with various flow control options. UART1 and UART3 can function as general
UART or can optionally function as IrDA interface.
The clock source for the UART1 and UART3 is:
APLL output
The clock source for the UART2 can be:
system clock or the sleep clock
APLL output
The main features of the UART peripherals include:
Selectable UART/autobaud modes
Dual 64-entry FIFOs for received and transmitted data payload
Programmable and selectable transmit and receive FIFO trigger levels for DMA and interrupt generation