Cirrus Logic CS5464 - Manual (Page 20)

CS5464
20 DS682F3
lists the functions of E3 as controlled by E3MODE[1:0]
in the Modes register when E1MODE is not enabled.
When both E2MODE bits are high, the E1MODE bits
are enabled, allowing active, apparent, reactive, or
wideband reactive energy for both energy channels to
be output on E1 and E2. Table 6 lists the functions of E1
and E2 with E1MODE enabled.
When E1MODE bits are enabled, the E3 pin outputs ei-
ther the power fail monitor status, or the sign of the E1
and E2 outputs. Table 7 list the functions of the E3 pin
using E3MODE[1:0] in the Modes register when
E1MODE is enabled .
6.8 No Load Threshold
The No Load Threshold register (Load
MIN
) is used to
zero out the contents of E
PULSE
and Q
PULSE
registers if
their magnitude is less than the Load
MIN
register value.
6.9 Energy Pulse Width
Note: Energy Pulse Width (PulseWidth) only applies to
E1, E2, or E3 pins that are configured to output pulses.
When any are configured to output steady-state signals,
such as voltage sign, energy channel in use, power fail
monitor, or energy sign, pulse widths and output rates
do not apply.
The pulse width time (t
pw
) in Figure 2 , is set by the value
in the PulseWidth register which is an integer multiple of
the sample or output word rate (OWR). At OWR of
4000 Hz (a period of 250 uS) t
pw
= PulseWidth x 250uS.
By default, PulseWidth is set to 1.
6.10 Energy Pulse Rate
The full-scale pulse frequency of enabled E1, E2, E3
pins is the PulseRate x output word rate (OWR)/2. The
actual pulse frequency is the full-scale pulse frequency
multiplied by the pulse register’s (E
PULSE
, S
PULSE
,
Q
PULSE
) value.
Example:
If the output word rate (OWR) is 4000 Hz, and the
PulseRate
is set to 0.05, the full-rate pulse frequency is
0.05 x 4000 / 2 = 100 Hz. If the E
PULSE
register, driving
E1, is 0.4567, the pulse output rate on E1 will be
100 Hz x 0.4567 = 45.67 Hz.
6.11 Voltage Sag/Current Fault Detection
Voltage sag detection is used to determine when aver-
aged voltage falls below a predetermined level for a
specified interval of time. Current fault detection deter-
mines when averaged current falls below a predeter-
mined level for a specified interval of time.
The specified interval of time (duration) is set by the val-
ue in the V1Sag
DUR
(V2Sag
DUR
) and I1Fault
DUR
(I2Fault
DUR
) registers. Setting any of these to zero (de-
fault) disables the detect feature for the given channel.
The value is in output word rate (OWR) samples. The
predetermined level is set by the values in the
V1Sag
LEVEL
(V2Sag
LEVEL
) and I1Fault
LEVEL
(I2Fault
LEVEL
) registers.
Since the values of V1 and V2 come from the same in-
put, only one voltage sag detector is necessary.
E3MODE1 E3MODE0 E3 output
0 0 Reactive Energy
0 1 Power Fail Monitor
1 0 Voltage Sign
1 1 Apparent Energy
Table 5. E3 Pin Configuration
E1MODE1 E1MODE0 E1 / E2 outputs
0 0 Active Energy
0 1 Apparent Energy
1 0 Reactive Energy
1 1 Wideband Reactive
Table 6. E1 / E2 Modes
E3MODE1 E3MODE0 E3 output
0 0 Power Fail Monitor
0 1 Energy Sign
1 0 not used
1 1 not used
Table 7. E3 Pin with E1MODE enabled