cs5461 Cirrus Logic, Inc., cs5461 Datasheet - Page 24

• Manufacturer Part Number: cs5461
• Description: Single-phase, Bidirectional Power/energy Ic
• Manufacturer: Cirrus Logic, Inc.

ative energy accumulation is reached in this regis-
ter, the CS5461 will issue either a positive or
negative energy pulse on the EOUT/EDIR pins.
After the pulse or pulses are issued, a certain resid-
ual amount of energy may be left over in this inter-
nal energy accumulation register. In this situation,
the residual energy is not lost or discarded, but rath-
er it is maintained and added to the energy that is
accumulated during the next update period.
5.2.2 Mechanical Counter Format
Setting the MECH bit in the Control Register to ‘1’
and the STEP bit to ‘0’ enables wide-stepping puls-
es for mechanical counters and similar discrete
counter instruments. In default mechanical mode
format, active-low pulses are 128 ms wide when
using a 4.096 MHz crystal and K = 1. When energy
is positive, the pulses appear on EOUT. When en-
ergy is negative, pulses appear on EDIR (see Fig-
ure 11). The pulse width is set in the Pulsewidth
register and will limit the pulse frequency avail-
able. It is up to the user to insure that pulses will not
occur at a rate faster than the 128 ms pulse dura-
tion, or faster than the mechanical counter can ac-
commodate. This is done by verifying that the
PulseRateE Register is set to an appropriate value.
Because in the default state the duration of each
pulse is set to 128 ms, the maximum output pulse
24
EOUT
EDIR
EOUT
EDIR
...
...
...
...
Figure 11. Mechanical Counter Format on EOUT and EDIR
Figure 12. Stepper Motor Format on EOUT and EDIR
Positive Energy
Positive Energy
128 ms
frequency
MCLK/K = 4.096 MHz). For values of MCLK/K
different than 4.096 MHz, the duration of one pulse
is (128*4.096 MHz)/(MCLK/K) milliseconds.
5.2.3 Stepper Motor Format
Setting the STEP bit in the Control Register to ‘1’
and the MECH bit to ‘0’ transforms the EOUT and
EDIR pins into two-phase stepper motor outputs.
When an energy pulse occurs, one of the outputs
changes state. When the next energy pulse occurs,
the other output changes state. The direction the
motor will rotate is determined by the order of the
state changes. When energy is positive, EOUT will
lead EDIR. When energy is negative, EDIR will
lead EOUT (see Figure 12).
5.3 FOUT Pulse Output
In many metering applications, the pulse frequency
to power rate on the EOUT pin may be set to a rel-
atively low value, such that the pulse frequency is
on the order of 1-100 Hz at nominal power con-
sumption levels. However, calibration can take a
long time at such output frequencies. In order to re-
duce the time needed to verify the meter an extra
pulse frequency-to-power output is provided on the
FOUT pin. The pulse frequency-to-power rate can
Negative Energy
128 ms
Negative Energy
is
limited
to
~7.8 Hz
...
...
...
...
CS5461
DS546F2
(for