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AFT
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DR
D
RAFT
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FT DRAF
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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
261 of 571
NXP Semiconductors
UM10316
Chapter 18: LPC29xx SPI0/1/2
3.2 SPI slave-enable register
The slave-enable register controls which slaves are enabled.
4
SLAVE_DISABLE
R/W
Slave-output disable (only relevant in slave
mode)
When multiple slaves are connected to a
single chip-select signal for broadcasting of
a message by a master, only one slave may
drive data on its transmit-data line since all
slave transmit-data lines are tied together to
the single master.
1
Slave cannot drive its transmit-data output
0*
Slave can drive its transmit-data output
3
TRANSMIT_MODE
R/W
Transmit mode
1
Sequential-slave mode
0*
Normal mode
2
LOOPBACK_MODE
R/W
Loopback-mode bit
Note: when the RX FIFO width is smaller
than the TX FIFO width the most significant
bits of the transmitted data will be lost in
loopback mode.
1
Transmit data is internally looped-back and
received
0*
Normal serial interface operation
1
MS_MODE
R/W
Master/slave mode
1
Slave mode
0*
Master mode
0
SPI_ENABLE
R/W
SPI enable bit
Slave mode:
If the SPI module is not enabled it will not
accept data from a master or send data to a
master.
Master mode:
If there is data present in the transmit FIFO
the SPI module will start transmitting. This
bit will also be set when the SPI module
receives a non-blocked enable trigger from
the external timer in sequential-slave mode.
In sequential-slave mode or when using the
external trigger this bit is self-clearing.
1
SPI enable
0*
SPI disable
Table 215. SPI_CONFIG register bit description (SPI_CONFIG0/1/2, addresses: 0xE004 7000
(SPI0), 0xE004 8000 (SPI1), 0xE004 9000 (SPI2))
…continued
* = reset value
Bit
Symbol
Access
Value
Description