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C0-microSD+ Handling and ESD Precautions

The C0-microSD+ is an electronic assembly with exposed contacts rather than a sealed consumer memory card. Standard electrostatic-discharge (ESD) precautions apply whenever you handle it, and a small number of operational rules protect the contents of its SPI flash. This page collects both.

ESD precautions​

The module carries an FPGA and an SPI flash behind unprotected interface pads, so a static discharge through those pads can damage the module or corrupt its stored contents.

  • Handle the module at an ESD-protected workstation where possible. Where that is not possible, ground yourself before touching the module, for example with an ESD wrist strap connected to a grounded bench.
  • Hold the module by its body edges. Avoid touching the eight microSD interface contacts and the second row of pads that carries the SPI configuration port and the user GPIOs.
  • Keep the module in antistatic packaging whenever it is not in a socket.
  • Treat the socket opening on the host as a user-accessible port, and fit host-side ESD protection to it in the same way you would protect any other memory card slot on the host board. See Design-In Guide → ESD and handling.

Do not format the module​

The C0-microSD+ enumerates as an unformatted block-storage device, because the addresses that a host reads and writes are the registers, buffers, and memory regions of the Signaloid SoC rather than a file system. If your operating system offers to format the module, dismiss the prompt. Formatting writes over the on-device data layout and can destroy a flashed application.

To confirm that a module is a C0-microSD+ and that its contents are intact, see Identify your module. If a module was formatted by accident, see Troubleshooting and FAQ.

Insertion and removal​

The C0-microSD+ is hot-swappable in normal operation, so you may insert it into a running host and remove it again in the same way as an ordinary microSD card.

  • Insert the module fully, until the socket mechanism seats it. A partially seated module either fails to enumerate or enumerates intermittently.
  • Align the module with the socket keying and let the mechanism do the work. Do not force a module into a socket that resists it, and do not insert it at an angle, because the interface pads and the socket contacts damage easily.
  • Release a push-push socket with the socket mechanism rather than by pulling on the body of the module.
warning

Never remove the module, and never remove power from the host, while a flash operation is in progress. Writing an application binary erases and reprograms whole sectors of the SPI flash, and losing power part way through such a write leaves the flash in an indeterminate state. Wait for the host tool to report that the operation finished before you touch the module.

See Flash an application.

The module needs no configuration step on insertion. Removing and reinserting the module power-cycles it. The module comes back with the core held in reset and every register at its default value, so start the core again to run your device application. See Start and stop the core.

Storage and environment​

Keep the module within its published operating and storage conditions. See Specifications → Operating Temperature.

When the module is not in use, keep it in antistatic packaging, away from moisture, condensation, and direct sunlight. Avoid containers that hold loose metal parts, because these scratch the exposed pads. Let a module that has been stored somewhere cold reach room temperature before you insert it, so that condensation does not form on the pads while the module is powered.

Cleaning​

Clean the interface pads only when contamination causes intermittent enumeration or causes read and write errors that reseating the module does not fix.

  • Wipe the pads with a lint-free swab lightly moistened with isopropyl alcohol. Wipe along the pads rather than across them.
  • Let the module dry completely before you insert it into a socket.
  • Do not use abrasives, do not use solvents other than isopropyl alcohol, and do not clean the module ultrasonically.
  • Do not immerse the module in liquid. The module is not sealed and carries no ingress-protection rating.

Next steps​

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