Errors and Diagnostics

How to read errors

• error() returns the last error code as a byte.
• error(VERBOSE) prints a message to serial and still returns the code.

Error Code Table

These values come from src/diagnostics.h.

Code	Name	Meaning
0x00	SUCCESS	Function completed successfully
0x01	CALLBEGIN	begin() was not called
0x02	UNKNOWNCHIP	Chip ID not recognized
0x03	UNKNOWNCAP	Capacity not identified
0x04	CHIPBUSY	Chip remained busy past timeout
0x05	OUTOFBOUNDS	Address exceeded memory limits with overflow disabled
0x06	CANTENWRITE	Write-enable latch could not be set
0x07	PREVWRITTEN	Target area already contains data
0x08	LOWRAM	Low RAM condition detected
0x09	SYSSUSPEND	Suspend/resume state error
0x0A	ERRORCHKFAIL	Post-write verification failed
0x0B	NORESPONSE	No chip response over SPI
0x0C	UNSUPPORTEDFUNC	Function unsupported by chip
0x0D	UNABLETO4BYTE	Could not enable 4-byte addressing
0x0E	UNABLETO3BYTE	Could not return to 3-byte addressing
0x0F	CHIPISPOWEREDDOWN	Operation attempted while powered down
0x10	NOSFDP	SFDP not available
0x11	NOSFDPERASEPARAM	SFDP erase parameters unavailable
0x12	NOSFDPERASETIME	SFDP erase timing unavailable
0x13	NOSFDPPROGRAMTIMEPARAM	SFDP program timing unavailable
0x14	NOCHIPSELECTDECLARED	Custom SPI constructor missing chip select
0xFE	UNKNOWNERROR	Unknown error state

Fast Debug Sequence (Beginners)

1. Call begin() in setup() and print getJEDECID().
2. If zero or invalid, check wiring and chip-select pin.
3. Call error(VERBOSE) after each failed operation.
4. For flash writes, erase region before writing.
5. Keep errorCheck=true until your setup is stable.

Best Practices

• Keep a small serial log of operation + returned error code.
• For production firmware, map key error codes into telemetry counters.
• Use FlashDiagnostics example sketch for initial bring-up.