Estoy probando un diseño BMS con varias placas esclavas, cada una de las cuales contiene un bq76PL536A conectado a un bus CAN común a través de un MCU ATmega32M1 y un transceptor aislado ISO1050DW. El problema al que me enfrento es que a veces uno de los bqs deja de medir los voltajes y las temperaturas de las celdas a las que está conectado y emite valores como 0V y ~ 65000 grados (después de la conversión del termistor), aunque todavía puedo dormir. Modo o hacer que encienda o apague el LED conectado a su GPIO (por lo que no está completamente fundido) y la única manera de resolver el problema es cambiar el chip. ¿Tienes alguna pista sobre por qué debería comportarse de esta manera?
Como referencia, este es el contenido de los registros de uno de los circuitos integrados defectuosos:
Register address: 0 - Register content: 11000001 (DEVICE_STATUS)
Register address: 1 - Register content: 0 (GPAI[0])
Register address: 2 - Register content: 0 (GPAI[1])
Register address: 3 - Register content: 0 (VCELL1[0])
Register address: 4 - Register content: 0 (VCELL1[1])
Register address: 5 - Register content: 0 (VCELL2[0])
Register address: 6 - Register content: 0 (VCELL2[1])
Register address: 7 - Register content: 0 (VCELL3[0])
Register address: 8 - Register content: 0 (VCELL3[1])
Register address: 9 - Register content: 0 (VCELL4[0])
Register address: A - Register content: 0 (VCELL4[1])
Register address: B - Register content: 0 (VCELL5[0])
Register address: C - Register content: 0 (VCELL5[1])
Register address: D - Register content: 0 (VCELL6[0])
Register address: E - Register content: 0 (VCELL6[1])
Register address: F - Register content: 0 (TEMPERATURE1[0])
Register address: 10 - Register content: 0 (TEMPERATURE1[1])
Register address: 11 - Register content: 0 (TEMPERATURE2[0])
Register address: 12 - Register content: 0 (TEMPERATURE2[1])
Register address: 13 - Register content: 0 (RSVD)
Register address: 14 - Register content: 0 (RSVD)
Register address: 15 - Register content: 0 (RSVD)
Register address: 16 - Register content: 0 (RSVD)
Register address: 17 - Register content: 0 (RSVD)
Register address: 18 - Register content: 0 (RSVD)
Register address: 19 - Register content: 0 (RSVD)
Register address: 1A - Register content: 0 (RSVD)
Register address: 1B - Register content: 0 (RSVD)
Register address: 1C - Register content: 0 (RSVD)
Register address: 1D - Register content: 0 (RSVD)
Register address: 1E - Register content: 0 (RSVD)
Register address: 1F - Register content: 0 (RSVD)
Register address: 20 - Register content: 0 (ALERT_STATUS)
Register address: 21 - Register content: 10 (FAULT_STATUS)
Register address: 22 - Register content: 0 (COV_FAULT)
Register address: 23 - Register content: 100000 (CUV_FAULT)
Register address: 24 - Register content: 0 (PRESULT_A)
Register address: 25 - Register content: 0 (PRESULT_B)
Register address: 26 - Register content: 0 (RSVD)
Register address: 27 - Register content: 0 (RSVD)
Register address: 28 - Register content: 0 (RSVD)
Register address: 29 - Register content: 0 (RSVD)
Register address: 2A - Register content: 0 (RSVD)
Register address: 2B - Register content: 0 (RSVD)
Register address: 2C - Register content: 0 (RSVD)
Register address: 2D - Register content: 0 (RSVD)
Register address: 2E - Register content: 0 (RSVD)
Register address: 2F - Register content: 0 (RSVD)
Register address: 30 - Register content: 1111101 (ADC_CONTROL)
Register address: 31 - Register content: 10000011 (IO_CONTROL)
Register address: 32 - Register content: 0 (CB_CTRL)
Register address: 33 - Register content: 0 (CB_TIME)
Register address: 34 - Register content: 0 (ADC_CONVERT)
Register address: 35 - Register content: 0 (RSVD)
Register address: 36 - Register content: 0 (RSVD)
Register address: 37 - Register content: 0 (RSVD)
Register address: 38 - Register content: 0 (RSVD)
Register address: 39 - Register content: 0 (RSVD)
Register address: 3A - Register content: 0 (SHDW_CTRL)
Register address: 3B - Register content: 10000001 (ADDRESS_CONTROL)
Register address: 3C - Register content: 0 (RESET)
Register address: 3D - Register content: 0 (TEST_SELECT)
Register address: 3E - Register content: 0 (RSVD)
Register address: 3F - Register content: 0 (E_EN)
Register address: 40 - Register content: 1110000 (FUNCTION_CONFIG)
Register address: 41 - Register content: 0 (IO_CONFIG)
Register address: 42 - Register content: 101101 (CONFIG_COV)
Register address: 43 - Register content: 1 (CONFIG_COVT)
Register address: 44 - Register content: 10111 (CONFIG_CUV)
Register address: 45 - Register content: 1 (CONFIG_CUVT)
Register address: 46 - Register content: 1010101 (CONFIG_OT)
Register address: 47 - Register content: 1 (CONFIG_OTT)
Register address: 48 - Register content: 0 (USER1)
Register address: 49 - Register content: 0 (USER2)
Register address: 4A - Register content: 0 (USER3)
Register address: 4B - Register content: 0 (USER4)
Como se puede ver, el bit DRDY (bit 0 en el registro DEVICE_STATUS) está establecido, afirmando que se ha completado una conversión, pero todos los registros de datos (voltajes y temperaturas) son nulos (verifiqué con un multímetro las diferencias de voltaje en Los pines del IC y son correctos). La única razón por la que puedo pensar por qué debería suceder es un bloqueo de bajo voltaje, pero el bit UVLO (bit 2 en el registro DEVICE_STATUS) no está configurado, por lo que este no es el caso (de todos modos VBAT = ~ 22V, por lo que no debería activar una UVLO).
