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UM10503
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© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
633 of 1441
NXP Semiconductors
UM10503
Chapter 24: LPC43xx/LPC43Sxx SPI Flash Interface (SPIFI)
24.6.5 SPIFI cache limit register
The SPIFI hardware includes caching of previously-accessed data to improve
performance. Software can write an address within the device to this register, to prevent
such caching at and above that address. After Reset this register contains the allocated
size of the SPIFI memory area, so that all possible accesses are below that value and are
thus cacheable.
24.6.6 SPIFI data register
After initiating a command that includes a data output field by writing to the Command
Register, software should write output data to this register. Store Byte instructions provide
one data byte, Store Halfword instructions provide two bytes, and Store Word instructions
provide 4 bytes of output data. Store commands are waited if the FIFO is too full to accept
the number of bytes being stored. For Store Halfword and Store Word, the least significant
byte is sent first.
After initiating a command that includes a data input field by writing to the Command
Register, software should read input data from this register. Load Byte instructions deliver
one data byte to software, Load Halfword instructions deliver two bytes, and Load Word
instructions deliver 4 bytes of input data. Load commands are waited if a command is in
progress and the FIFO does not contain the number of bytes being loaded. For Load
Halfword and Load Word commands, the least significant byte is received first.
DATALEN bytes should be read from or written to this register. If such a (read or write)
command needs to be terminated before that time, software should write a 1 to the
RESET bit in the Status register to accomplish this. If software attempts to read or write
more data than was specified in DATALEN, a Data Abort exception will occur.
In polling mode (see the POLL bit in the SPIFI command register), one byte must be read
from this register because the poll mechanism writes the matching byte.
This register is not used for commands initiated by reading the flash address range in the
memory map. In DMA transfers in peripheral to-or-from-memory mode, the address of this
register should be used as the peripheral address.
24.6.7 SPIFI memory command register
Before accessing the flash area of the memory map, software should set up the device.
After optionally writing to the Intermediate Data register, software should write a word to
this register to define the command that is used to read data. Thereafter data can be read
from the flash memory area, either directly or by means of a DMA channel.
Table 452. SPIFI cache limit register (CLIMIT, address 0x4000 3010) bit description
Bit
Symbol
Description
Reset value
31:0
CLIMIT
Zero-based upper limit of cacheable memory
0x0800 0000
Table 453. SPIFI Data register (DATA, address 0x4000 3014) bit description
Bit
Symbol
Description
Reset
value
31:0
DATA
Input or output data
0