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writeChar

Signatures

  • bool SPIFlash::writeChar(uint32_t _addr, int8_t data, bool errorCheck = true)
  • bool SPIFram::writeChar(uint32_t _addr, int8_t data, bool errorCheck = true)

What It Is For

Write one int8_t value to memory at a specific address.

Parameters

  • _addr: Target start address in memory.
  • data: Value to persist.
  • errorCheck: When true, read-back verification is performed after write for stronger integrity checking.

Behavior Details

For flash, target region must be erased beforehand (typically 0xFF) for reliable programming. FRAM usually allows direct overwrite without explicit erase, but capacity checks still apply.

Return Semantics

Returns true when write sequence completes (and optional verification passes). Returns false on address, power-state, bus, or verification errors.

Failure Behavior

Common failures: out-of-range address, flash not erased, chip busy, powered-down device, or SPI signal integrity problems.

Common Mistakes

  • Writing to flash without erasing target region first.
  • Ignoring false return and not checking error(VERBOSE).
  • Reusing addresses without a clear storage map.

Choosing Between Similar APIs

  • Use this typed write when your payload is exactly this type.
  • Use writeAnything() for composite structs.
  • Use array/string writes when storing variable-length data.

Example

uint32_t addr = 0;
// flash.eraseSector(addr); // required for flash if not erased
bool ok = flash.writeChar(addr, -10);
if (!ok) flash.error(VERBOSE);