lpc2917 NXP Semiconductors, lpc2917 Datasheet - Page 27

• Manufacturer Part Number: lpc2917
• Description: Arm9 Microcontroller With Can And Lin
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC2917_19_1
Preliminary data sheet
8.4.4.4 UART clock description
8.4.5.1 Overview
8.4.5.2 Functional description
8.4.5 Serial peripheral interface
The UART modules are clocked by two different clocks; CLK_SYS_PESS and
CLK_UARTx (x = 0-1), see
branch clock for power management. The frequency of all CLK_UARTx clocks is identical
since they are derived from the same base clock BASE_CLK_UART. The register
interface towards the system bus is clocked by CLK_SYS_PESS. The baud generator is
clocked by the CLK_UARTx.
The LPC2917/19 contains three Serial Peripheral Interface modules (SPIs) to allow
synchronous serial communication with slave or master peripherals.
The key features are:
The SPI module is a master or slave interface for synchronous serial communication with
peripheral devices that have either Motorola SPI or Texas Instruments Synchronous
Serial Interfaces.
The SPI module performs serial-to-parallel conversion on data received from a peripheral
device. The transmit and receive paths are buffered with FIFO memories (16 bits wide x
32 words deep). Serial data is transmitted on SPI_TxD and received on SPI_RxD.
The SPI module includes a programmable bit-rate clock divider and prescaler to generate
the SPI serial clock from the input clock CLK_SPIx.
The SPI module’s operating mode, frame format, and word size are programmed through
the SLVn_SETTINGS registers.
A single combined interrupt request SPI_INTREQ output is asserted if any of the
interrupts are asserted and unmasked.
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Master or slave operation
Supports up to four slaves in sequential multi-slave operation
Supports timer-triggered operation
Programmable clock bit rate and prescale based on SPI source clock
(BASE_SPI_CLK), independent of system clock
Separate transmit and receive FIFO memory buffers; 16 bits wide, 32 locations deep
Programmable choice of interface operation: Motorola SPI or Texas Instruments
Synchronous Serial Interfaces
Programmable data-frame size from 4 to 16 bits
Independent masking of transmit FIFO, receive FIFO and receive overrun interrupts
Serial clock-rate master mode: fserial_clk d f
Serial clock-rate slave mode: fserial_clk = f
Internal loopback test mode
Rev. 1.01 — 15 November 2007
Section
7.2.2. Note that each UART has its own CLK_UARTx
ARM9 microcontroller with CAN and LIN
CLK(SPI)*
CLK(SPI)*
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LPC2917/19
© NXP B.V. 2007. All rights reserved.
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