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Host Requirements
The host sends this command to cause the decoder to beep. The host may also send these beep codes as part of the PARAM_SEND
directive.
Decoder Requirements
When the decoder receives this command, it beeps the sequence provided in the BEEP directive. If ACK/NAK handshaking is enabled,
the decoder ACKs if a valid beep code is requested. Otherwise it sends NAK_DENIED.
CMD_ACK
Description: Positive acknowledgment of received packet
Packet Format
Length
0x04
Field Descriptions
Field Name
Length
Opcode
Message
Source
Status
Data
Checksum
This message is sent to the SSI packet transmitter when the received packet passes the checksum check and no negative
acknowledgment conditions apply (see CMD_NAK). If the data is in response to a command (e.g., PARAM_REQUEST,
REQUEST_REVISION, etc.), no ACK is sent.
ACK/NAK handshaking can be disabled, but this is not recommended.
It is not necessary to respond to a valid ACK or NAK message.
Host Requirements
The decoder must send a CMD_ACK or response data within the programmable Serial Response Time-out to acknowledge receipt of
all messages, unless noted otherwise in the message description section. If the host sends data and does not receive a response
within the programmable serial response time-out, it resends the message (with the retransmit status bit set) before declaring a
failure. The host should limit the number of retries.
Decoder Requirements
The decoder must send a CMD_ACK or response data within the programmable Serial Response Time-out to acknowledge receipt of
all messages, unless noted otherwise in the message description section. If the decoder does not receive an ACK within this time
period, it sends the previous message again. The decoder retries twice more (with the retransmit status bit set) before declaring a
transmit error.
Opcode
Message Source
0xD0
Format
Length of message (not
including checksum).
0xD0
0 = Decoder
4 = Host
Bit 0: Retransmit
Bit 1-7: unused
2's complement sum of
2 Bytes
message contents excluding
checksum.
Status
Data
Size
Description
1 Byte
Length Field
1 Byte
Identifies this Opcode type.
1 Byte
Identifies where the message is coming
from.
1 Byte
Identifies the transmission status.
All unused bits must be set to 0.
None
Checksum of message.
Simple Serial Interface 10-7
Checksum
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