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AFT
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DR
D
RAFT
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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
263 of 571
NXP Semiconductors
UM10316
Chapter 18: LPC29xx SPI0/1/2
[1]
The RX_FIFO_READMODE register can change the effect of reading this register.
3.5 SPI receive FIFO POP register
The receive-FIFO POP register is used in RX FIFO PROTECT mode (see
) to pop the first element from the receive FIFO.
3.6 SPI receive-FIFO read-mode register
The receive-FIFO read-mode register configures the SPI RX FIFO read mode.
Table 218. FIFO_DATA register bit description (FIFO_DATA0/1/2: addresses 0xE004 700C
(SPI0), 0xE004 800C (SPI1), 0xE004 900C (SPI2))
* = reset value
Bit
Symbol
Access
Value
Description
31 to
16
reserved
R
-
Reserved; do not modify. Read as logic 0
15 to 0 FIFO_DATA
R/W
0000h*
This register is used to access the FIFOs:
Writing data puts new data in the transmit
FIFO.
Reading data reads a word from the receive
FIFO
Table 219. RX_FIFO_POP register bit description (FIFO_POP0/1/2: addresses 0xE004 7010
(SPI0), 0xE004 8010 (SPI1), 0xE004 9010 (SPI2))
Bit
Symbol
Access
Value
Description
31 to 1 reserved
R
-
Reserved; do not modify. Read as logic 0
0
RX_FIFO_POP
W
1
Pops the first element from the receive FIFO.
This is necessary in RX FIFO PROTECT
mode because reading the FIFO_DATA
register will not cause the receive FIFO
pointer to be updated. This is to protect the
receive FIFO against losing data because of
speculative reads.