BQ79600-Q1: bq79616 not waking up through bq79616

MounishPatel Seetha

Intellectual 770 points

Part Number: BQ79600-Q1
Other Parts Discussed in Thread: BQ79616

Tool/software:

bq79600 is responding and i am able to read data.

Now I have connected bq79600(COMH_p) to bq79616(COML_P) similarly N. After bq79600 wake ping. I am sending following

81 00 03 09 01 2F 8E

to wake up stack devices. Is this ok or should I send DIR_SEL=1 before this? attaching my schematic..Please check if the isolation transformer (HMU1228NL) is ok?

update:

I have also tried by sending data in the following sequence

Hardware: Removed, transformed,r and connected a 2.2nf i.e used capacitive isolation

Some observed info: bq79616-->COMP,COMN : 2.5V,2.5V bq79600-->COMP,COMN : 2.195V,2.195V

1. Wakeup ping on bq7900

2. DIRE SEL=1: 81 0 3 9 80 EF EE ( As I am using COMHP,COMHN and left COMLN,COMLP unused)

3. Send a wakeup to the stack 81 0 3 9 20 EF 96

Kindly please check where am I gng wrong

Thanks&Regards

Mounish

2 months ago

0 Benjamin Luty 2 months ago

TI__Expert 6460 points

Mournish,

MounishPatel Seetha said:
81 00 03 09 01 2F 8E

This is an invalid command. You are telling the device that you are writing two bytes, but only send one data byte. This will cause communication to freeze until a COMM_CLEAR tone is sent. Please refer to section 7.3.7.1 of the datasheet for details on the data communication protocol.

Regards,

0 MounishPatel Seetha 2 months ago in reply to Benjamin Luty

Intellectual 770 points

Can you please share

1.sample command to select DIRSEL=1 and

2. To send wakeup command to stack devices?

Thanks & Regards

Mounish

0 Benjamin Luty 2 months ago in reply to MounishPatel Seetha

TI__Expert 6460 points

Mounish,

1) 0xD0 0x03 0x09 0x80 0xCF 0x14

2) 0xD0 0x03 0x09 0x40 0xCF 0x44

Regards,

0 MounishPatel Seetha 2 months ago in reply to Benjamin Luty

Intellectual 770 points

0xD0 0x03 0x09 0x40 0xCF 0x44

How will the above command send wakeup? It looks like it will send the shutdown command, right? Please find the datasheet snip.

also to not change dir_SEL.. it should be 0x40 should be replaced by 0xA0 right?

Thanks&Regards

Mounish

0 Benjamin Luty 2 months ago in reply to MounishPatel Seetha

TI__Expert 6460 points

Mounish,

MounishPatel Seetha said:
0xD0 0x03 0x09 0x40 0xCF 0x44

Yes, my mistake, this should be 0xD0 0x03 0x09 0x20 0xCF 0x6C.

The commands should not be sent at the same time. It takes time for the direction to switch from forward to backward. It is unlikely that you will have to wait in the code as it is very fast, but you cannot send the instructions as one command.

Regards,

0 MounishPatel Seetha 2 months ago in reply to Benjamin Luty

Intellectual 770 points

Hi BO,

but sending 0x20 again will change the DIR_SEL bit 1 to 0, right?

if this changes, then the datasheet we should wait for some time . Please recommend

Thanks&Regards

Mounish

0 Benjamin Luty 2 months ago in reply to MounishPatel Seetha

TI__Expert 6460 points

Mounish,

No, sending 0x20 to 0x309 will always set the communication direction to reverse.

Regards,

0 MounishPatel Seetha 2 months ago in reply to Benjamin Luty

Intellectual 770 points

I am slightly confused here

DIR_SEL Select daisy chain comm direction. Not self-clear bit.
0: In a device, command frame travels from MCU to COMH
1: In a device, command frame travels from MCU to COML

Can you please explain?

what if I want to reset DIR_SEL to zero?

finally you are saying that

1) 0xD0 0x03 0x09 0x80 0xCF 0x14

2) 0xD0 0x03 0x09 0x20 0xCF 0x6C

right?

Thanks&Regards

Mounish

+1 Benjamin Luty 2 months ago in reply to MounishPatel Seetha

TI__Expert 6460 points

MounishPatel Seetha said:
DIR_SEL Select daisy chain comm direction. Not self-clear bit.
0: In a device, command frame travels from MCU to COMH
1: In a device, command frame travels from MCU to COML

This is correct

MounishPatel Seetha said:
what if I want to reset DIR_SEL to zero?

Send a write with data 0x00. This will set the bit to zero.

MounishPatel Seetha said:
finally you are saying that

1) 0xD0 0x03 0x09 0x80 0xCF 0x14

2) 0xD0 0x03 0x09 0x20 0xCF 0x6C

If you are using the reverse direction (MCU -> COML) you will want to send the DIR_SEL command first (as seen is table 7-10 of the datasheet) then send the WAKE tone. If you are using the forward direction, you can simply omit the command that sets DIR_SEL as it defaults to zero.

Regards,

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BQ79600-Q1: bq79616 not waking up through bq79616