LPC2925 NXP Semiconductors, LPC2925 Datasheet - Page 27

• Manufacturer Part Number: LPC2925
• Description: (LPC2921 - LPC2925) ARM9 microcontroller
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC2921_2923_2925_0
Preliminary data sheet
www.DataSheet4U.com
6.12.5.1 Functional description
6.12.5.2 Pin description
The SPI module can operate in:
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 ×
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.
Depending on the operating mode selected, the SPI_CS_OUT outputs operate as an
active-HIGH frame synchronization output for Texas Instruments synchronous serial
frame format or an active-LOW chip select for SPI.
Each data frame is between four and 16 bits long, depending on the size of words
programmed, and is transmitted starting with the MSB.
The SPI pins are combined with other functions on the port pins of the
LPC2921/2923/2925, see
y runs from 0 to 3).
Table 15.
[1]
[2]
Symbol
SPIx SCSy
SPIx SCK
SPIx SDI
SPIx SDO
•
•
•
•
Serial clock-rate slave mode: fserial_clk = f
Internal loopback test mode
Master mode:
– Normal transmission mode
– Sequential slave mode
Slave mode
Direction of SPIx SCS and SPIx SCK pins depends on master or slave mode. These pins are output in
master mode, input in slave mode.
In slave mode there is only one chip select input pin, SPIx SCS0. The other chip selects have no function in
slave mode.
SPI pins
Pin name
SCSx[y]
SCKx
SDIx
SDOx
Rev. 00.01 — 24 October 2008
Section
Direction
IN/OUT
IN/OUT
IN
OUT
6.11.3.
Description
SPIx chip select
SPIx clock
SPIx data input
SPIx data output
Table 15
ARM9 microcontroller with CAN and LIN
CLK(SPI)
LPC2921/2923/2925
shows the SPI pins (x runs from 0 to 2;
[1]
/4
[1][2]
© NXP B.V. 2008. All rights reserved.
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