25 lines
877 B
Plaintext
25 lines
877 B
Plaintext
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STC12A
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This is an early STC12 protocol variant; It seems to be used on STC12Cx052 and
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possibly other models. It is a mix of STC89 and STC12 protocol versions.
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Differences to STC12:
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* Uses NONE parity instead of EVEN parity.
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* Checksum calculations are different: only a single-byte modular sum is used.
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* Baudrate handshake isn't initiated with a type 0x50 packet; this is simply
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skipped.
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* After the handshake a special ping-pong sequence of 0x80 type packets needs
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to be sent.
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This doesn't appear to serve any purpose - possibly this is just done to
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verify that the connection works reliably. STC12 doesn't require it anymore
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because parity and the improved checksum ensure correct operation.
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* Erase is acknowledged with type 0x80 packet instead of type 0x00
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* After flash programming, there is no finish packet, type 0x69, sent; this
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is simply skipped.
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