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Hi,
According to the datasheet of CYBT_343026, this pin should not control from external CPU.
(Please see attached "DS_CYBT.png")
However, this pin could be used to enter "Recovery Mode" according to EVAL board manual and following link.
Programming an EZ-BT WICED Module – KBA223428
Should the customer connect SPI2_MOSI from host CPU or button and sensed "Low" if data corruption in SPI Flash is happened ?
Thank you.
--TAK
Solved! Go to Solution.
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Hi TAK,
The Recovery mode is activated at Device Boot up time, either during Power On or Reset.
Hence a Pull Up would be advised, to make sure the SPI2_MISO pin is not accidentally 'Low' during Power On & Reset Conditions.
Once chip boot is complete then the SPI functions normally.
As for the value of the Pull up I do not have a precise value to recommend, but based on my understanding & experience 10K should work.
Winston
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Attached "DS_CYBT.png"
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Hi TAK,
If you may have to reprogram the CYBT_343026, then its better to keep a recovery button on SPI Mosi . Because some times when you try reprogram the device, the programmer may fail to detect the device. To recover this situation , recovery button have to be used along with reset button.
In this case, please have a recovery button. You may refer the CYBT_343026 Eval board schematics for the same.,
Thanks,
Anjana
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Hi Anjana,
According to the following URL, I understand procedure to program FW under Recovery mode is following sequence.
Programming an EZ-BT WICED Module – KBA223428
<Procedure under recovery mode>
1.Sense Low of SPI2_MOSI
2.Power-cycle(Off => On)
3.Module boot-up as recovery mode and start programming.
-----
<Question>
Q1: Is my understanding correct?
Q2: In this procedure, I think SPI2_MOSI is shorted to CYW20706 SPI2_MOSI pin inside CYBT module and CYW20706 may be corrupted.
In order to avoid it, I think there is following idea
1. There is a resistor on this line in CYBT module so tthe module will not get damage.
2. Before sense Low this SPI2_MOSI, host CPU should assert XRES pin to reset the module to avoid short then de-assert XRES.
Should the customer do #2 idea or other implementation from host CPU side?
Thank you.
--TAK
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Hi Anjana,
The customer needs to know exact recovery sequence.
In the other notes(that was asked from my customer), you provided following sequence.
After download to the CYBT-343026-EVAL at the first time,I can never download to CYBT-343026-EVAL
<Recovery Procedure>
1. Press and hold RECOVER button (SW2) |
2. Press and hold RESET button (SW1) for 1 second |
3. Release SW1 |
4. Release SW2 |
5. Re-program the board |
They needs to know following points that is including my previous question.
<Question>
Q1: In this sequence, is there any possibility to get damage in the CYW20706 by shorting SPI2_MOSI from external CPU?
If there is no damage, please tell me how?
Q2: How long time should the customer has waiting time between #3 and #4 ?
10ms from releasing XRES pin to releasing SPI2_MOSI is enough ?
Thank you.
--TAK
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Hi anpm
my customer design is stopped by this question so could you take it as soon as possible???
Thank you.
--TAK
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Hi TAK,
Q1: No there is no chance for damage for the chip. But I think since its connected to an external MCU, you may connect pull up resistor on the SPI lines.
Suppose if a scenario comes similar to recovery procedure, and SPI line goes low to high in between a reset then there is a chance that chip will get into recovery mode and will wait for a new program download . At this time application will stop running (unless you press a reset again) assuming that flash is corrupted. So to avoid this situation (unnecessary low - high transition on SPI line) , you may connect pull up resistor.
Q2: Our Module team have tested with 100ms in large production.
Thanks & Regards,
Anjana
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Hi anpm
Thanks.
For just in case, could you tell me recommended resistor value of pull-up on SPI2_MOSI.
I'm not sure whether there is internal pull-up or something.
If there is, we need to care resistor value for it.
Thank you.
--TAK
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Hi anpm
Sorry for many questions.
>Q1: No there is no chance for damage for the chip.
Do you mean that external CPU sense "Low" to SPI2_MOSI during module is power-on ?
Is that correct?
The customer is assuming that current procedure is under power-off state but I think it is under power-on.
In summary, the following procedure is right way to enter recovery mode.
<Recovery Procedure>
0. Power-On
1. RECOVER(SPI2_MOSI) set Low
2. XRES set Low more than 1 second
3. Release XRES
4. Release RECOVER(SPI2_MOSI) after 100ms
5. Re-program the board
Thank you.
--TAK
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Hi TAK,
The Recovery mode is activated at Device Boot up time, either during Power On or Reset.
Hence a Pull Up would be advised, to make sure the SPI2_MISO pin is not accidentally 'Low' during Power On & Reset Conditions.
Once chip boot is complete then the SPI functions normally.
As for the value of the Pull up I do not have a precise value to recommend, but based on my understanding & experience 10K should work.
Winston
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Hi Winston,
Thanks for that,
The customer will implement open-drain buffer(Hi-Z 0.1MΩ) on SPI2_MOSI.
I think it is useful.
If it is not good idea, please let me know.
Thank you.
--TAK