UM10850
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User manual
Rev. 2.4 — 13 September 2016
319 of 464
NXP Semiconductors
UM10850
Chapter 23: LPC5410x I2C-bus interfaces (I2C0/1/2)
23.6.5 Time-out value register
The TIMEOUT register allows setting an upper limit to certain I
2
C bus times, informing by
status flag and/or interrupt when those times are exceeded.
Two time-outs are generated, and software can elect to use either of them.
1. EVENTTIMEOUT checks the time between bus events while the bus is not idle: Start,
SCL rising, SCL falling, and Stop. The EVENTTIMEOUT status flag in the STAT
register is set if the time between any two events becomes longer than the time
configured in the TIMEOUT register. The EVENTTIMEOUT status flag can cause an
interrupt if enabled to do so by the EVENTTIMEOUTEN bit in the INTENSET register.
2. SCLTIMEOUT checks only the time that the SCL signal remains low while the bus is
not idle. The SCLTIMEOUT status flag in the STAT register is set if SCL remains low
longer than the time configured in the TIMEOUT register. The SCLTIMEOUT status
flag can cause an interrupt if enabled to do so by the SCLTIMEOUTEN bit in the
INTENSET register. The SCLTIMEOUT can be used with the SMBus.
.
23:20 -
Reserved. Read value is undefined, only zero should be written.
NA
24
EVENTTIMEOUTCLR Event time-out interrupt clear.
0
25
SCLTIMEOUTCLR
SCL time-out interrupt clear.
0
31:26 -
Reserved. Read value is undefined, only zero should be written.
NA
Table 350. Interrupt Enable Clear register (INTENCLR, address offset 0x00C) bit description
…continued
Bit
Symbol
Description
Reset value
Table 351. Address map TIMEOUT register
Peripheral
Base address
Offset
Increment
Dimension
I2C0
0x4009 4000
0x010
-
1
I2C1
0x4009 8000
0x010
-
1
I2C2
0x4009 C000
0x010
-
1
Table 352. Time-out value register (TIMEOUT, address offset 0x010) bit description
Bit
Symbol
Description
Reset
value
3:0
TOMIN
Time-out time value, bottom four bits. These are hard-wired to 0xF. This gives a minimum
time-out of 16 I
2
C function clocks and also a time-out resolution of 16 I
2
C function clocks.
0xF
15:4
TO
Time-out time value. Specifies the time-out interval value in increments of 16 I
2
C function clocks,
as defined by the CLKDIV register. To change this value while I
2
C is in operation, disable all
time-outs, write a new value to TIMEOUT, then re-enable time-outs.
0x000 = A time-out will occur after 16 counts of the I
2
C function clock.
0x001 = A time-out will occur after 32 counts of the I
2
C function clock.
...
0xFFF = A time-out will occur after 65,536 counts of the I
2
C function clock.
0xFFF
31:16 -
Reserved. Read value is undefined, only zero should be written.
NA