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UM10503
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© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
1342 of 1441
NXP Semiconductors
UM10503
Chapter 48: 12-bit ADC (ADCHS)
The ADC wake-up time from power down is configured by RECOVERY_TIME. This value
should be set to 0x90. This gives a recovery time of 0x90/fADC; for fADC=80 MHz this
gives 1.80 µs.
48.6.9 Threshold A/B register
This register sets the lower and upper threshold levels for automatic threshold comparison
for input channels linked to threshold comparator A (or B). Linking a channel to a
threshold comparator is controlled by descriptor field TRESHOLD_SEL (see
A conversion result less than the THR_LOW_A (or THR_LOW_B) value on the linked
channel will cause the THCMP_RANGE status bits for that channel to be set to 0b01. This
result will also generate an interrupt 1 request if enabled to do so via the SET_EN1 bits
associated with the comparator THCMP_BRANGE bits in the SET_EN1 register.
A conversion result greater than the THR_HIGH_A (or THR_HIGH_B) value on the linked
channel will cause the THCMP_RANGE status bits for that channel to be set to 0b10. This
result will also generate an interrupt 1 request if enabled to do so via the SET_EN1 bits
associated with the comparator THCMP_ARANGE bits in the SET_EN1 register.
If, for two successive conversion results on a given channel, one result is below a
threshold and the other is equal-to or above this threshold, then a threshold crossing has
occurred. In this case the THCMP_CROSS (see
) status bits will indicate
that a threshold crossing has occurred. A threshold crossing event will also generate an
interrupt 1 request if enabled to do so via the SET_EN1 bits associated with each channel
in the SET_EN1 register.
Remark:
The levels assume offset binary coded data; TWOS is set to 0 (see
Table 1129.Configuration register (CONFIG, address 0x400F 001C) bit description
Bit
Symbol
Description
Reset
value
1 : 0
TRIGGER__MASK
00 = triggers off
01 = software trigger only
10 = external trigger only
11 = both triggers allowed
0x0
3:2
TRIGGER_MODE
00 = rising external trigger
01 = falling external trigger
10 = low external trigger
11 = high external trigger
0x0
4
TRIGGER_SYNC
0 = do not synchronize external trigger input
1 = synchronize external trigger input
0x0
5
CHANNEL_ID_EN
0 = do not add channel ID to FIFO output data
1 = add channel ID to FIFO output data
0x0
13:6
RECOVERY_TIME
ADC recovery time from power down
0x90
31:14
-
Reserved
-