71M6533 Datasheet, PDF (54/132 Pages) Teridian Semiconductor Corporation – Energy Meter IC

71M6533/G/H and 71M6534/H Data Sheet
FDS_6533_6534_004
If enabled with the IEN_WD_NROVF bit in I/O RAM, an interrupt occurs roughly 1 ms before the WDT resets
the chip. This can be used to determine the cause of a WDT reset since it allows the code to log its state
(e.g. the current PC value, loop counters, flags, etc.) before a WDT reset occurs.
1.5.13 Test Ports (TMUXOUT Pin)
One of the digital or analog signals listed in Table 49 can be selected to be output on the TMUXOUT pin.
The function of the multiplexer is controlled with TMUX[4:0] (I/O RAM 0x20AA[4:0]), as shown in Table 49.
The TMUXOUT pin may be used for diagnosis purposes or in production test. The RTC 1-second output
may be used to calibrate the crystal oscillator. The RTC 4-second output provides even higher precision.
TMUX[4:0]
0
1
2
3
4
5
6
7
8 - 0x0F
0x10
0x11
0x12
0x13
0x14
0x15
0x16
0x17
0x18
0x19
0x1A
0x1B
0x1C
0X1D
0X1E
0X1F
Table 49: TMUX[4:0] Selections
Mode
Analog
Analog
Analog
Analog
Analog
Analog
Analog
Analog
–
Digital
Digital
–
Digital
Digital
Digital
Digital
Digital
Digital
Digital
–
Digital
Digital
Digital
Digital
Digital
Function
GNDD
Reserved
GNDD
Reserved
PLL_2P5
Output of the 2.5 V low-power regulator
Internal VBIAS voltage (nominally 1.6V)
Not used
Reserved
RTC 1-second output
RTC 4-second output
Not used
V1 comparator output, synchronized to RTCLK
Real-time output from the CE
WDTR_EN (comparator 1 output AND V1LT3)
V2 comparator output (71M6534 only)
V1 comparator output, unsynchronized
RXD (from Optical interface, w/ optional inversion)
MUX_SYNC
Not used
CKMPU (MPU clock)
Pulse output
RTCLK (output of the oscillator circuit, nominally 32,786Hz)
CE_BUSY (busy interrupt generated by CE, 396µs)
XFER_BUSY (transfer busy interrupt generated by the CE,
nominally every 999.7ms)
1.5.14 V2 Comparator (71M6534/6534H Only)
The 71M6534/6534H offers a pin that is connected to an internal comparator. The voltage applied to this
pin is compared to the internal reference voltage (VBIAS). If the voltage at the V2 pin is above VBIAS,
the comparator output will be high (1). The comparator output is reflected at the TMUXOUT pin, when
0x16 is selected for TMUX[4:0].
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