50 lines
1.3 KiB
Markdown
50 lines
1.3 KiB
Markdown
\page stack FPC embedded stack
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The communication stack implemented on the embedded devices by FPC follows the following
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specification.
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\image html stack.svg "HCP embedded stack"
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\image latex stack.eps "HCP embedded stack"
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\section phy Physical
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The physical layer have a fixed size buffer of 256 bytes.
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\section link Link
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The link layer handles packet consistency.
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Each packet received is acknowledged on the link layer, if an error occurs no retransmission is
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done on this level, instead the error is propagated upwards.
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Channel | Size | Payload | CRC |
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------- | ------- | ---------- | ------- |
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2 bytes | 2 bytes | size bytes | 4 bytes |
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All fields are using unsigned data types.
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\section tsp Transport
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The transport layer handles packet segmentation.
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As the PHY MTU is 256 bytes the maximum payload per segment is 242 bytes.
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Errors are propagated upwards.
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Size | Seq Nr | Seq Len | Payload |
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------- | ------- | ------- | ---------- |
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2 bytes | 2 bytes | 2 bytes | size bytes |
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All fields are using unsigned data types.
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\section app Application
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The application layer is a optional security layer, the default implementation is clear text
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(unsecure).
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If a security solution is used it will be part of that products documentation.
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\section hcp HCP
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The HCP frame is described in the \link hcpf HCP frame format section.
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