SPI Packets

Decoder-to-Host Packet Descriptions

END OF FRAME (EOF)

The EOF bit is set when the FLEXchip IC is in All Frame mode and the end of frame has been reached. The FLEXchip IC is in All Frame mode if the all frames mode enable counter is non-zero, if any temporary address enabled counter is non-zero, or if the FAF bit in the All Frame Mode Packet is set. The bit is cleared when read. This bit is initialized to 0 when the FLEXchip IC is reset.

BUFFER OVERFLOW ERROR (BOE)

The BOE bit is set when information has been lost due to slow host response time. When the SPI transmit buffer on the FLEXchip IC overflows, the FLEXchip IC clears the transmit buffer, turns off decoding by clearing the ON bit in the Control Packet, and sets this bit. The bit is cleared when read. This bit is initialized to 0 when the FLEXchip IC is reset.

UNUSED BITS (x)

The value of these bits is not guaranteed.

Part ID Packet

The Part ID Packet is sent by the FLEXchip IC whenever the FLEXchip IC is disabled due to the checksum feature (see Checksum Packet on B-6). Since the FLEXchip IC is disabled after reset, this is the first packet that will be received by the host after reset. The ID of the Part ID Packet is 255 (decimal).

Table B-39 Part ID Packet Bit Assignments

MODEL (MDL)

This identifies the FLEXchip model. Current value is 0.

COMPATIBILITY ID (CID)

This value describes what other parts with the same model number are compatible with this part. Current value is 1. Any future versions of FLEXchip that have MDL set to 0 and CID0 set to 1 will be 100% compatible to this version.