AN3157

Circuit description

Doc ID 17105 Rev 1

9/26

When configured in peripheral operating mode, the SPI port is enabled and some

microcontroller-based applications can either read internal data records or write the mode

and configuration signals by means of a dedicated protocol, or reset the device.

By default, the STPMC1 is configured in peripheral mode (configuration bits APL=0).

This also implies the following output settings:

●

watchdog reset signal on the MON pin

●

zero-crossing (ZCR) on the MOP pin

●

programmable energy pulsed output on the LED pin

For further information on STPMC1 programmable bit settings please refer to the device

datasheet.

The P1 connector is also used during the evaluation phase to connect the measurement

module to a PC through the STPMxx parallel programmer/reader hardware interface.

This allows the user to set the internal STPMC1 registers temporarily and/or permanently,

using a dedicated GUI.

The VOTP pin on the P1 connector is used when a host wants to permanently write some

configuration bits in the STPMC1 device. In this case, a +15 V power level must be present

on the VOTP. This level must be delivered from the host itself because the module does not

have an on-board charge pump.

Table 4.

P1 connector pin description

Pin

Pin name

Functional description

1

VOTP

Power supply input of +15.0 V during permanent write to OTP cells

2

---

Not connected

3

GND

Signal reference level 0 V and power supply return

4

SDA-TD

SPI interface data

5

SCS

SPI interface enable

6

SCL-NLC

SPI interface clock

7

---

Not connected

8

SYN-NP

SPI interface signal

9

---

Not connected

10

VCC

Power out of +3.3 or 5 V