UM10850
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User manual
Rev. 2.4 — 13 September 2016
323 of 464
NXP Semiconductors
UM10850
Chapter 23: LPC5410x I2C-bus interfaces (I2C0/1/2)
23.6.9 Master Time register
The MSTTIME register allows programming of certain times that may be controlled by the
Master function. These include the clock (SCL) high and low times, repeated Start setup
time, and transmitted data setup time.
The I
2
C clock pre-divider is described in
.
3
MSTDMA
Master DMA enable. Data operations of the I
2
C can be performed with DMA.
Protocol type operations such as Start, address, Stop, and address match
must always be done with software, typically via an interrupt. When a DMA
data transfer is complete, MSTDMA must be cleared prior to beginning the
next operation, typically a Start or Stop.This bit is read/write.
0
0
Disable. No DMA requests are generated for master operation.
1
Enable. A DMA request is generated for I
2
C master data operations. When
this I
2
C master is generating Acknowledge bits in Master Receiver mode, the
acknowledge is generated automatically.
31:4 -
Reserved. Read value is undefined, only zero should be written.
NA
Table 358. Master Control register (MSTCTL, address offset 0x020) bit description
Bit
Symbol
Value Description
Reset value
Table 359. Address map MSTTIME register
Peripheral
Base address
Offset
Increment
Dimension
I2C0
0x4009 4000
0x024
-
1
I2C1
0x4009 8000
0x024
-
1
I2C2
0x4009 C000
0x024
-
1
Table 360. Master Time register (MSTTIME, address offset 0x024) bit description
Bit
Symbol
Value Description
Reset value
2:0
MSTSCLLOW
Master SCL Low time. Specifies the minimum low time that will be asserted by
this master on SCL. Other devices on the bus (masters or slaves) could
lengthen this time. This corresponds to the parameter t
LOW
in the I
2
C bus
specification. I
2
C bus specification parameters t
BUF
and t
SU;STA
have the same
values and are also controlled by MSTSCLLOW.
6
0x0
2 clocks. Minimum SCL low time is 2 clocks of the I
2
C clock pre-divider.
0x1
3 clocks. Minimum SCL low time is 3 clocks of the I
2
C clock pre-divider.
0x2
4 clocks. Minimum SCL low time is 4 clocks of the I
2
C clock pre-divider.
0x3
5 clocks. Minimum SCL low time is 5 clocks of the I
2
C clock pre-divider.
0x4
6 clocks. Minimum SCL low time is 6 clocks of the I
2
C clock pre-divider.
0x5
7 clocks. Minimum SCL low time is 7 clocks of the I
2
C clock pre-divider.
0x6
8 clocks. Minimum SCL low time is 8 clocks of the I
2
C clock pre-divider.
0x7
9 clocks. Minimum SCL low time is 9 clocks of the I
2
C clock pre-divider.
3
-
Reserved.
0