TIDUEM8B March 2019 – February 2021
The MSP432 MCU and ADS131M04 portion of this design is powered from a single voltage rail (DVCC), which can be derived from two potential methods. In the first method, DVCC can be powered directly by connecting a 3.3-V external power supply at the DVCC header J9 and GND. To support this direct way of driving DVCC, a jumper should not be placed on jumper header J2.
In the second method of driving DVCC, the DVCC voltage is produced from the 3.3-V output of a TPS70933 LDO. In this second method, place a jumper at jumper header J2 and apply 5 V between J4 and GND to provide the necessary input voltage to the TPS70933. If a jumper is placed both at jumper headers J1 and J2, the 5-V rail applied at header J4 is used to power DVCC as well as the current-limited rail produced by the TPS25921L.
Various jumper headers and jumper settings are present to add to the flexibility to the board. Some of these headers require that jumpers be placed appropriately for the board to correctly function. Table 3-1 indicates the functionality of each jumper on the board.
The headers with (WARNING) text in the MAIN FUNCTIONALITY column are not isolated, so measuring equipment should not be used there (especially for the one-voltage configuration, which has the system ground connected to a line voltage) when running off the Mains. This applies, unless either isolators external to the board of the design are used to connect at the headers, if the equipment is battery powered and does not connect to Mains, or if AC mains is isolated.
| HEADER OR HEADER OPTION NAME | TYPE | MAIN FUNCTIONALITY | VALID USE-CASE | COMMENTS |
|---|---|---|---|---|
| J1 | 2-pin jumper header | TPS25921L input rail selection (WARNING) | Place a jumper at this header to use the voltage applied at the J4 header as the TPS2591L input voltage. A current-limited version of this input voltage is provided at the output of the TPS25921L. To use a different voltage than what is applied at J4, apply an external voltage at this header and do not place a jumper here. | If a jumper is placed at J1 and another jumper is at J2, the TPS25921L input voltage and DVCC is supplied from the same source (header J4) so only one external power supply is necessary. If it is desired to use a separate power supply for DVCC and the TPS25921L, then the jumper at J1 can be removed and the desired TPS25921L can be applied directly at pin 2 of the J1 header. Alternatively, instead of removing the jumper at J1, the jumper at J2 can be removed and 3.3 V can be applied directly at the DVCC header instead of using the voltage at the J4 header and the TPS70933 LDO to generate the 3.3-V rail for DVCC. |
| J2 | 2-pin jumper header | TPS70933 DVCC output selection (WARNING) | Place a jumper at this header to generate the 3.3-V rail for DVCC from the TPS70933 LDO and the voltage applied at J4. Apply 3.3 V directly at the DVCC header J9 and do not place a jumper here to bypass using the TPS70933. | If a jumper is placed at J1 and another jumper is at J2, the TPS25921L input voltage and DVCC is supplied from the same source (header J4) so only one external power supply is necessary. If it is desired to use a separate power supply for DVCC and the TPS25921L, then the jumper at J1 can be removed and the desired TPS25921L can be applied directly at pin 2 of the J1 header. Alternatively, instead of removing the jumper at J1, the jumper at J2 can be removed and 3.3 V can be applied directly at the DVCC header instead of using the voltage at the J4 header and the TPS70933 LDO to generate the 3.3-V rail for DVCC. |
| J3 | 4-pin header | Current-limited, 5-V rail (WARNING) | Connect this header and GND to any radios or radio modules that you want to current-limit. | If a jumper is placed at J1, this is the current-limited version of the voltage applied at header J4. This current-limited voltage also appears at pin 1 of header J12. |
| J4 | 4-pin header | 5-V input (WARNING) | Apply 5 V between here and GND to create the 5-V current-limited output at J3 and to create a 3.3-V output that can be connected to DVCC. | To create the current-limited output at J3 from J4, place a jumper at J1. To create the 3.3 V at DVCC from J4, place a jumper at J2. |
| J5 | 2-pin header | Header connected to TPS25921 FLTb, and EN/UVLO pins (WARNING) | Probe at pin 2 of this header to determine if the TPS25921L has asserted its fault flag. Probe at pin 1 for the state of the EN/UVLO pin of the TPS25921L. | During a TPS25921L thermal shutdown event, the load connected to the out pin of the TPS25921L is disconnected from the source connected to the VIN pin. As a result, header J3 will not anymore be a current-limited version of the voltage applied to J4. The EN/UVLO can be driven low by the microcontroller to try to reconnect the source of the TPS25921L device at its input pin to the load at its output pin. In the test software, a maximum of one retry attempt is made after a thermal shutdown event. |
| J6 | 2-pin jumper header | TPS25921L output connection (WARNING) | Place a jumper here to connect the TPS25921L out pin to header J3, thereby creating a current-limited version of the rail applied at the VIN pin of the TPS2591L device. | Place a jumper here. |
| J7 | 2-pin header | THVD1500 RE and DE pin (WARNING) | Probe at this header to view the signal fed to the RE and DE pins of the THVD1500 device, which determines when the receiver or driver is enabled. | This header has two pins: GND and PM1, where PM1 is the P2.7 GPIO pin of the MSP432 MCU that drives the RE and DE pins of the THVD1500 device. |
| J8 | 4-pin header | MSP432 ADC14 and reference header (WARNING) | Probe here to provide inputs to ADC channels A0 and A1 as well as the ADC14 reference input. | The test software does not use this header. This header is added if it is desired to add custom sensing code with the 14-bit SAR ADC of the MSP432 MCU. |
| J9 | 4-pin header | DVCC voltage header (WARNING) | Probe here for DVCC voltage. Connect the positive terminal of the bench or external power supply when powering the board externally directly through DVCC instead of using the TPS70933 LDO. | If DVCC is powered from the TPS70933 LDO (jumper is placed at header J2), probe between here and J10 to measure the output voltage from the TPS70933. If DVCC is powered externally directly (remove the jumper from header J2), 3.3 V must be applied between here and J10. |
| J10 | 4-pin header | Ground voltage header (WARNING) | Probe here for GND voltage. Connect negative terminal of bench or external power supply when powering the board externally directly through DVCC instead of using the TPS70933 LDO. | If DVCC is powered from the TPS70933 LDO (jumper is placed at header J2), probe between here and J9 to measure the output voltage from the TPS70933. If DVCC is powered externally directly (remove the jumper from header J2), 3.3 V must be applied between J9 and this header. |
| J11 | 4-pin header | Header containing MSP432 P7.0, 7.1, P7.2, and P7.3 pins (WARNING) | Probe here for P7.0, P7.1, P7.2, and P7.3 GPIO pins. | The P7.0, P7.1, and P7.2 pins are used for adjusting contrast of the LCD. P7.3 is not used in this design. These pins are all port mappable. If the LCD is not needed, it can be disabled in software and R5, R11, R12, and R13 can be removed so that P7.0, P7.1, and P7.2 can be port mapped for other purposes such as potentially communicating to an external radio or radio module. If these pins are used for communicating to an external radio or radio module, header J12 can be used for powering these external modules and current limiting the power to them so that if there are any external shorts it does not affect powering the metrology. |
| J12 | 2-pin header | Current-limited rail (WARNING) | Connect this header to an external module to provide a current-limited 5-V rail to an external module. | Pin 1 of this header is the current-limited output rail from the TPS25921L, which is also available at header J3. Pin 2 of this header is the GND connection. For a 5-V, current-limited voltage to appear here, apply 5 V at header J4, and place jumpers on J1 and J6. |
| J13 | 10-pin 2-row connector | JTAG: MSP432 programming header (WARNING) | Connect the MSP-FET- 432ADPTR adapter to this connector to power the MSP432 MCU. | The MSP-FET-432ADPTR is used to allow the MSP-FET tool to program the MSP432 device. One connector of the MSP-FET-432ADPTR adapter connects to the FET tool and the other connector connects to the JTAG connector of the MSP432 MCU. Note that the MSP432 has to be powered externally to program the MSP432 MCU. Since this header and the FET tool is not isolated, do not connect to this header when running off Mains and Mains is not isolated. |
| J16 | 2-pin header | Active energy pulses (WARNING) | Probe here for cumulative active energy pulses. This header has two pins: GND and ACT, which is where the active energy pulses is actually output. | This header is not isolated from AC mains, so do not connect measuring equipment here (especially for the one-voltage configuration) See the "ISO_ACT" pin of J18 instead, which is isolated. If it is desired to test the active power pulses, use the "ISO_ACT" pin of J18 instead since it is isolated. |
| J17 | 2-pin header | Reactive energy pulses (WARNING) | Probe here for cumulative reactive energy pulses. This header has two pins: GND and REACT, which is where the reactive energy pulses is actually output. | This header is not isolated from AC mains, so do not connect measuring equipment here (especially for the one-voltage configuration). If it is desired to test the reactive power pulses, use the "ISO_REACT" pin of J18 instead since it is isolated. |
| J18 | 4-pin header | Isolated pulses header | Probe here for the isolated cumulative active energy pulses and the isolated cumulative three-phase reactive energy pulses. Using these header for pulses is recommended, especially for the one-voltage configuration since the system will be referenced with respect to one of the line voltages in this configuration. | This header has four pins: ISO_GND, ISO_REACT, ISO_ACT, and ISO_VCC. ISO_GND is the isolated ground for the energy pulses. ISO_VCC is the VCC connection for the isolated active and reactive energy pulses. ISO_ACT is where the isolated active energy pulses are output. ISO_REACT is where the isolated active energy pulses are output. This header is isolated from AC mains so it is safe to connect to scope or other measuring equipment because isolators are already present. However, either 3.3 V or 5 V must be applied between ISO_GND and ISO_VCC to produce the active energy pulses and reactive energy pulses at this header. The produced pulses have a logical high voltage that is equal to the voltage applied between ISO_GND and ISO_VCC. |
| J19 | 3-pin jumper header | RS-232 or RS-485 selection-power | Place a jumper at either the RS-232 or RS-485 positions depending on which of these two communication options are desired. | Put a jumper in the RS-232 position on this header, J20, and J21 to select RS-232 communication. Put a jumper in the RS-485 position on this header, J20, and J21 to select RS-485 communication. |
| J20 | 3-pin jumper header | RS-232 or RS-485 selection-TX | Place a jumper at either the RS-232 or RS-485 positions depending on which of these two communication options are desired. | Put a jumper in the RS-232 position on this header, J19, and J21 to select RS-232 communication. Put a jumper in the RS-485 position on this header, J19, and J21 to select RS-485 communication. |
| J21 | 3-pin jumper header | RS-232 or RS-485 selection-RX | Place a jumper at either the RS-232 or RS-485 positions depending on which of these two communication options are desired. | Put a jumper in the RS-232 position on this header, J19, and J20 to select RS-232 communication. Put a jumper in the RS-485 position on this header, J19, and J20 to select RS-485 communication. |
| J22 | 2-pin header | Header containing RS232_3.3, which is the voltage source harvested from RS-232 line, and RS232_GND, which is the ground connection for the isolated RS-232 | Probe here for the isolated 3.3-V supply generated on the side of the isolation barrier with the RS-232. | Note that the 3.3-V rail produced here is derived from the RS-232 port of the PC so it is not applicable when using RS-485 mode. For RS-485 mode, external power must be provided to power the THVD1500 RS-485 transceiver. |
| J23 | 2-pin jumper header | TX_EN: RS-232 transmit enable (WARNING) | Place a jumper here to enable RS-232 transmissions. | |
| J24 | 2-pin jumper header | RX_EN: RS-232 receive enable (WARNING) | Place a jumper here to enable receiving characters using RS-232. | |
| J25 | 4-pin terminal block | RS-485 connection | Connection point for RS-485 | To view the GUI using RS-485, connect the USB to RS-485 adapter here. 5 V must be provided externally on pin 1 of this header. Pin 2 of this header is the RS-485 ground, pin 3 is the B bus I/O line, and pin 4 is the A bus I/O line. |
| J26 | 3-pin terminal block | Phase A (two-voltage configuration) or Line A (one-voltage configuration) CT connection (WARNING) | Current inputs after the sensors for line A | This terminal block is a three-position terminal block but only the leftmost and rightmost positions are used. The center position, which is connected to GND, is not connected to the CT. Connect the positive terminal of the CT to the terminal block position on the most left, which is labeled "POS". Connect the negative terminal of the CT to the terminal block position on the most right, which is labeled "NEG". Before performing any test, verify that this terminal block is securely connected to both output leads of the CT. Note that the order of the CT leads is reversed here compared to the order on J27 |
| J27 | 3-pin terminal block | Phase B (two-voltage configuration) or Line B (one-voltage configuration)CT connection (WARNING) | Current inputs after the sensors for line B | This terminal block is a three-position terminal block but only the leftmost and rightmost positions are used. The center position, which is connected to GND, is not connected to the CT. Connect the positive terminal of the CT to the terminal block position on the most right, which is labeled "POS". Connect the negative terminal of the CT to the terminal block position on the most left, which is labeled "NEG". Before performing any test, verify that this terminal block is securely connected to both output leads of the CT. Note that the order of the CT leads is reversed here compared to the order on J26. |
| J28 | 2-pin terminal block | Phase A voltage (WARNING) | Phase A line connection | For the two-voltage configuration, this terminal block is connected to the Neutral voltage and phase A line voltage connections on the reference design case using wires. For the one-voltage configuration, this terminal block is connected to line B instead of neutral. Connect the pin on the terminal block denoted by a "NEG" on the PCB silk screen to neutral (two-voltage configuration) or line B (one-voltage configuration). The pin on the terminal block denoted by a "POS" on the PCB silk screen to the line of Phase A. The neutral connection on J28 and J29 are all connected to each other on the PCB. This is the Phase A line voltage connection, so only probe here if using equipment that could measure the Mains voltage. Note that the order of the phase input and neutral is reversed here compared to the order on J29 |
| J29 | 2-pin terminal block | Phase B voltage (WARNING) | Phase B line connection | For the two-voltage configuration, this terminal block is connected to the Neutral voltage and phase B line voltage connections on the reference design case using wires. For the one-voltage configuration, this terminal block is not used. Connect the pin on the terminal block denoted by a "NEG" on the PCB silk screen to neutral. Connect the pin on the terminal block denoted by a "POS" on the PCB silk screen to the line of Phase B. The neutral connection on J28 and J29 are all connected to each other on the PCB. This is the Phase B line voltage connection so only probe here if using equipment that could measure the Mains voltage. Note that the order of the phase input and neutral is reversed here compared to the order on J28. Also, this terminal block is not used for one-voltage configurations. |
| J30 | 2-pin jumper header | ADS131M04 AVDD jumper (WARNING) | A short (either through jumper of ammeter) must be present at this jumper header for proper operation of the ADS131M04. | This header along with J31 allow measuring the current consumption of the ADS131M04. |
| J31 | 2-pin jumper header | ADS131M04 DVCC jumper (WARNING) | A short (either through jumper of ammeter) must be present at this jumper header for proper operation of the ADS131M04. | This header along with J30 allow measuring the current consumption of the ADS131M04. |
| J32 | 8-pin header | ADS131M04 MSP432 communication header (WARNING) | Probe here for connections to the chip select signal, SPI signals, RST signal, CLKIN signal, and DRDY signal of the ADS131M04 device. | The
RST pin of the ADS131M04 device is used to reset the ADS131M04. When initializing the ADS131M04, the MSP432 drives this pin to reset the ADS131M04. The DRDY pin of the ADS131M04 device is used to alert the MSP432 MCU that new current samples are available. The CLKIN pin is fed from the SMCLK clock output of the MSP432 MCU to the ADS131M04 device, which divides the clock down to produce the used modulator clock. This header is not isolated from AC mains, so do not connect measuring equipment when running from Mains unless isolators external to the reference design are available. The pin mappings on this header are as follows: ● Pin 1: SMCLK (ADS131M04 CLKIN pin) ● Pin 2: SPI DOUT (ADS131M04 DIN pin/SIMO) ● Pin 3: SPI DIN (ADS131M04 DOUT/ pinSOMI ● Pin 4: SPI CLK (ADS131M04 SCLK pin) ● Pin 5: ADS DRDY (ADS131M04 DRDY pin) ● Pin 6: SPI CS (ADS131M04 CS pin) ● Pin 7: RST SYNC (ADS131M04 SYNC/ RESET pin) ● GND |