78M6612-IM/F View Datasheet(PDF) - Teridian Semiconductor Corporation

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78M6612-IM/F

Single-Phase, Dual-Outlet Power and Energy Measurement IC

Teridian Semiconductor Corporation 

DS_6612_001

78M6612 Data Sheet

2.2 Fault and Reset Behavior

2.2.1 Reset Mode

When the RESET pin is pulled high, all digital activity stops. The oscillator and RTC module continue to

run. Additionally, all I/O RAM bits are set to their default states. As long as V1, the input voltage at the

power fault block, is greater than VBIAS, the internal 2.5 V regulator continues to provide power to the

digital section.

Once initiated, the reset mode persists until the reset timer times out. This occurs in 4096 cycles of the

real time clock after RESET goes low, at which time the MPU begins executing its preboot and boot

sequences from address 00.

2.2.2 Power Fault Circuit

The 78M6612 includes a comparator to monitor system power fault conditions. When the output of the

comparator falls (V1<VBIAS), the PLL status bits in the I/O RAM are zeroed and the IC power downs.

Once system power returns, the MPU remains in reset and does not start until 2048 to 4096 CK32 clock

cycles later. Program execution starts at address 0x00. MPU RAM will be re-initialized.

2.3 Data Flow

The data flow between the Compute Engine (CE) and the MPU is shown in Figure 6. In a typical

application, the 32-bit CE sequentially processes the samples from the current and voltage inputs on pins

IA, VA, IB, and VB, performing calculations to measure active power (Wh), reactive power (VARh), A2h,

and V2h for four-quadrant measurement. These measurements are then accessed by the MPU,

processed further and output using the peripheral devices available to the MPU.

Pulses

Samples

CE

Pr -

Proecesso

r

IRQ

Data

MP

UPos -

Prot cesso

r

Processed

Metering

Data

I/O RAM (Configuration RAM)

Figure 6: MPU/CE Data Flow

Rev 2

19

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