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PSoC™ 4 Forum Discussions

GrCa_1363456
Level 5
First comment on KBA First comment on blog 250 sign-ins
Level 5

Is there programmable logic in a PSoC that's active before running a "Start" for the individual component or logic section?

Specifically, what programmable logic or pin states within a PSoC are functional at power up before the MCU is Active or reset is released?

Greg

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Len_CONSULTRON
Level 9
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Level 9

Greg,

Theoretically no PLD logic is active (or configured) before the MCU is active.

This is because the PLD logic switches are register/RAM based.  These registers are reset to default values at reset and need to be set by the MCU almost immediately after the reset is released.

Additionally for many of the components that use an Init() API call, the control register that "powers" the PLD logic is turned off at reset.

Having said that... there are Non-Volatile latches that are preserved through a reset on many if not ALL the digital GPIO pins.  They are defined at design-time and are the default logic settings for these pins on reset.  Note:  These latches should not be changed in SW at run-time.  This is because, although non-volatile, that have only about 100 write endurance specification.

Len

Len
"Engineering is an Art. The Art of Compromise."

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Len_CONSULTRON
Level 9
1000 replies posted 750 replies posted 500 likes received
Level 9

Greg,

Theoretically no PLD logic is active (or configured) before the MCU is active.

This is because the PLD logic switches are register/RAM based.  These registers are reset to default values at reset and need to be set by the MCU almost immediately after the reset is released.

Additionally for many of the components that use an Init() API call, the control register that "powers" the PLD logic is turned off at reset.

Having said that... there are Non-Volatile latches that are preserved through a reset on many if not ALL the digital GPIO pins.  They are defined at design-time and are the default logic settings for these pins on reset.  Note:  These latches should not be changed in SW at run-time.  This is because, although non-volatile, that have only about 100 write endurance specification.

Len

Len
"Engineering is an Art. The Art of Compromise."