xe8802 Semtech Corporation, xe8802 Datasheet - Page 186

• Manufacturer Part Number: xe8802
• Description: Data Acquisition Soc With 16+10 Bit Zoomingadc? Embedded Risc Controller And Lcd Driver
• Manufacturer: Semtech Corporation

21.5 VLD operation
The VLD is controlled by VldRange, VldTune and VldEn. VldRange selects the voltage range to be detected,
while VldTune is used to fine-tune this voltage level in 8 steps. VldEn is used to enable (disable) the VLD with a
1(0) value respectively. Disabled, the block will dissipate no power.
Note 1: absolute precision of the threshold voltage is ±10%.
Note 2: this timing is respected in case the internal RC or crystal oscillators are selected. Refer to the clock block
documentation in case the external clock is used.
To start the voltage level detection, the user sets bit VldEn. The measurement is started. After 2ms, the bit
VldValid is set to indicate that the measurement results are valid. From that time on, as long as the VLD is
enabled, a maskable interrupt request is sent if the voltage level falls below the threshold. One can also poll the
VLD and monitor the actual measurement result by reading the VldResult bit of the RegVldStat. This result is only
valid as long as the VldValid bit is ‘1’.
© Semtech 2006
symbol
T
T
Vth
EOM
PW
Minimum pulse width
Threshold voltage
description
measurement
duration of
detected
Table 21-5: Voltage level detector operation
XE8802 Sensing Machine Data Acquisition MCU
min
21-3
with ZoomingADC™ and LCD driver
Note 1
1.53
1.44
1.36
1.29
1.22
1.16
1.11
1.06
3.06
2.88
2.72
2.57
2.44
2.33
2.22
2.13
typ
875
2.0
1350
max
2.5
unit
ms
us
V
VldRange
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
trimming values:
comments
Note 2
Note 2
VldTune
www.semtech.com
000
001
010
011
100
101
110
111
000
001
010
011
100
101
110
111