ST UM3144 Evaluation Board For L9678 Airbag And Battery Cut-Off IC
Introduction
The L9678-S-EVB evaluation board is an evaluation board designed to provide to the user a platform for the evaluation of the L9678P or L9678P-S devices. The board provides all the main input/output capabilities needed to properly drive all IC inputs and outputs and to provide diagnostic functionalities
Hardware description
The L9678-S-EVB evaluation board has been developed to evaluate the L9678P or L9678P-S devices and test all their functionalities.
Its main features are:
- L9678P/L9678P-S placed into a socket allowing an easy change of the samples
- Possibility to solder L9678P/L9678P-S directly on the PCB
- Total accessibility to all pins through test points
- Presence of jumpers to fix the desired set up configuration
- Possibility to interface the board with SPC56P-Discovery board
L9678-S-EVB evaluation board
Board layout
Assembly Top
Assembly Bottom
Jumpers and connectors description
On Table 1 the name of each jumper on the board is listed while their default setting (closed or open) is reported in green; the name of the connectors and test points present on the board is also remarked
Jumpers and connectors description
| # | Name | J = Jumper C = Connector | Function | Closed | Open |
| J1 | PGND | J | Connection of PGND to GND | Power ground connected to common ground(1) | – |
| J2 | WDT | J | To disable the watchdog timer | Watchdog disabled | Watchdog enabled(1) |
| J3 | J | To set VCC to 5 V or to 3.3 V | 1-2 closed: VCC connected to VDD3V3 2-3 closed: VCC connected to VDD5(1) | – | |
| J4 | VBAT | C | Battery voltage | – | – |
| J5 | IGN | J | To wake-up the device | Device waked-up(1) | Device not waked-up |
| J6 | J | Connection of L9678 RESET pin to GPIO or RESET pin of μC | 1-2 closed: RESET_L96xx connected to uC RESET pin 2-3 closed: RESET_L96xx connected to μC GPIO0 pin | – | |
| J7 | SAFING INPUT | J | Connection of safing FET gate to VSF directly or through MUN5332DW | 1-2 closed: safing FET enabled via uC 2-3 closed: safing FET always enabled | Safing FET disabled |
| J8 | J | To discharge the ER capacitor | ER capacitor shorted to ground | ER capacitor charged(1) | |
| J9 | J | To connect the ER cap negative to ground | Cap negative connected to ground(1) | Cap negative not connected to ground | |
| J10 | HEADER34X4 | C | To connect the L9678 demo board to discovery board | – | – |
| J11 | J | To connect ISOK bus | 2-3 closed: ISO bus enabled(1) | – | |
| J12 | J | Not used for L9678 | – | ||
| J13 | BGND | J | Connection of BGND to GND | Boost ground connected to common ground(1) | – |
| J15 | J | Reserve voltage diagnostic (VRES) | VRES can be connected to ERBOOST, VBAT or VSUP | Reserve voltage is not diagnosed | |
| J16 | J | Not used for L9678 | |||
| J17 | J | Connection of VCC to VCC_Micro | VCC connected to VCC_Micro | VCC and VCC_Micro disconnected(1) | |
| J18 | C | SPI interface connector | – | – | |
| J19 | C | SPI interface connector | – | – | |
| J20 | AGND | J | Connection of AGND to GND | Analog ground connected to common ground(1) | – |
| J28 | J | RSU power supply | 1-2 closed: RSU power supply connected to VSUP(1) 2-3 closed: not used for L9678 | No RSU power supply |
| # | Name | J = Jumper C = Connector | Function | Closed | Open |
| J29 | J | To connect the ER cap positive to VER | Cap positive connected to VER(1) | Cap positive not connected to VER | |
| J30 | C | Airbag standard connector | – | – |
Default condition.
Test point list
| Designator | Name | Function |
| TP1 | FENH | FENH monitoring |
| TP2 | FENL | FENL monitoring |
| TP3 | COVRACT | COVRACT monitoring |
| TP4 | ACL | ACL monitoring |
| TP5 | ARM1 | ARM/ARM1 monitoring |
| TP6 | WDT | WDT monitoring |
| TP7 | ERBOOST | ERBOOST monitoring |
| TP8 | uc_SAFING | Monitoring of μC safing FET enable |
| TP9 | VIN monitoring | |
| TP10 | VDD3P3 | VDD3P3 monitoring |
| TP11 | BVSUP | BVSUP monitoring |
| TP12 | SAFING OUTPUT | SAFING OUTPUT monitoring |
| TP13 | VSUP | VSUP monitoring |
| TP14 | SS01 | SS01 monitoring |
| TP15 | SS23 | SS23 monitoring |
| TP16 | SS45 | SS45 monitoring |
| TP17 | SS67 | SS67 monitoring |
| TP18 | SS89 | SS89 monitoring |
| TP19 | SSAB | SSAB monitoring |
| TP20 | CVDD monitoring | |
| TP21 | VBATMON monitoring | |
| TP22 | BVVD5 | BVVD5 |
| TP23 | VDD5 | VDD5 monitoring |
| TP24 | SYNCBOOST monitoring (only L9679/80) | |
| TP25 | Monitoring of Q5 collector voltage | |
| TP26 | Monitoring of μC diagnostic enable | |
| TP27 | SATBCK monitoring | |
| TP28 | VCC monitoring | |
| TP29 | RSU4 monitoring | |
| TP30 | RSU3 monitoring | |
| TP31 | RSU1 monitoring | |
| TP32 | RSU0 monitoring | |
| TP33 | GND | GND monitoring |
| TP34 | CS_RS | CS_RS monitoring (only L9680) |
| TP35 | SPI_CS | SPI CS monitoring (only L9679/80) |
| TP36 | GND | GND monitoring |
| TP37 | GND | GND monitoring |
| TP38 | GND | GND monitoring |
| Designator | Name | Function |
| TP39 | GND | GND monitoringC |
Revision history
Document revision history
| Date | Version | Changes |
| 02-Mar-2023 | 1 | Initial release. |
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