KVAL
K
PGFS
GFS
PKUR
PKUA
Control, synchronization,
and clock division
load
load
PGEN
LFXT
(32 kHz)
PCEN
clr
PCCLR
1
7
-b
it
co
u
n
te
r
Control and
synchronization
load
1
6
-b
it
re
a
d
re
g
ist
e
r
PCRR
PCRA
C
PU
a
cce
ss,
re
a
d
o
r
w
ri
te
(n
o
t
su
rvi
vi
n
g
L
PM
3
.5
)
C
PU
a
cce
ss,
re
a
d
o
n
ly
PCR
PC
en
Pulse Counter
Pulse Generator
PCOFL
PG and PC in RTC power domain
PG and PC internal registers on RTC brownout
3
.5
3
.5
3
.5
3
.5
3
.5
load
load
iGFS
iK
8-bit counter
...
...
Internal
Test
Pulse
T
e
st
p
u
lse
o
u
tp
u
t
fu
n
ct
io
n
T
e
st
p
u
lse
in
p
u
t
fu
n
ct
io
n
3.5
T
PI
E
T
PO
E
T
PI
SEL
PGUR
PGUA
f
G
(grid frequency)
AC
T
IVAT
E
T
e
st
p
u
lse
e
n
a
b
le
f
u
n
ct
io
n
D
e
vi
ce
Po
rt
L
o
g
ic
Port Control Sync
syn
0
0
1
1
p
o
rt
re
q
u
e
st
syn
syn
PGCLR
MTIF Operation
624
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Metering Test Interface (MTIF)
23.2.8 Enabling the Pulse Generator and the Pulse Counter
The configuration bits MTIFPGCNT.PGEN and MTIFPCCNF.PCEN are expected to be static during a
regular metering operation. At start-up of the meter application, a reset caused by the RST pin after
recovery from an power loss, the MTIF behaves as follows:
The prescaler of the pulse generator is cleared when the pulse generator is disabled. After the application
enables MTIFPGCTL.PGEN, the pulse generation starts after 2 to 3 cycles (with the LF clock at 32 kHz).
Even though the pulse counter may be cleared independent of MTIFPGCTL.PCEN, make sure that the
counter is cleared either before or after 2 to 3 LFCLK cycles to avoid conflicts.
The pulse counter increments on high active pulses. Shorter pulses (artifacts) may be generated when
enabling and disabling the MTIF output pin. A complete MTIFPCCTL.PCEN disable and enable cycle can
cause up to two increments of the pulse counter when using the external pulse input pin.
23.3 MTIF Block Diagram
shows the interior of the MTIF module with an 3-pin MTIF I/O configuration. The dashed lines
represent the power domain crossings to areas that are powered in LPM0 to LPM3.5.
Figure 23-4. MTIF Block Diagram
23.3.1 Test Interface Input
The input does not feature any filter logic. To filter low-frequency contact bouncing, use an external RC
filter. For higher ESD, EMI, and RFI tolerance, use appropriate shielding and filtering. The enable function
of the test interface input is located in a separate register to fulfill the functional isolation requirement of
various regulations.
The MTIF module supports one input and one output, which can be on separate pins or on a shared pin,
depending on the specific device.