MagTek IntelliStripe65 99875161 - Manual (Page 74)

IntelliStripe 65 Command Reference
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MCP ERROR RECOVERY ENABLE PROPERTY
Property ID: 03 (Hex)
Property Type: Boolean
Power Up/Reset Value: 01 (hex) (True)
Get/Set/Save support: All
Description:
This property enables or disables the MCP error recovery feature. This feature is enabled if this
property is set to 1 (true) or disabled if this property is set to 0 (false).
Disabling this property will greatly reduce the development effort required to implement the
MCP protocol. In fact, disabling this property will reduce the protocol to simply sending and
receiving I-frames with the exception of the optional auto baud synchronization S-frame
sequence. However, disabling this property will also disable the error recovery feature of the
protocol. The error recovery feature of the protocol allows the protocol to automatically recover
from minor communication channel problems without requiring intervention from the
application layer. Users that have reliable communications channels do not need the error
recovery feature, so most users do not require this feature. Users that are writing their own MCP
USB drivers are encouraged to disable this property to help simplify the driver development
effort. If this property is disabled and it is not made non-volatile by using the Save property
command, then this property should be set as the first I-frame sent to the device after power up to
avoid having to implement any of the error recovery aspects of the protocol.
Disabling this property will change the following aspects of the MCP protocol from the devices
perspective.
• The protocol will no longer automatically recover from minor communications channel
problems.
• The device will no longer check the send and receive sequence numbers received from
the host. The host is no longer required to maintain these sequence numbers. They can
always be set to zero.
• The device will no longer require the host to acknowledge I-frames that it sent. The
device will assume that the host received the I-frame correctly. The host is no longer
required to send R-frames. The device will never send the host a polling R-frame. The
block wait timeout (BWT) is no longer used. The device will no longer send the host an
R-frame if takes longer than 250ms (BWT) to begin sending a response I-frame due to a
request I-frame (command) that takes some time to complete.
• The device will no longer require the host to establish a connection by sending a
RESYNC S-frame request. The device will be ready to accept I-frames as soon as baud
synchronization is completed.
The device will still enforce the protocols character wait timeout (CWT) and so should the host.
This is required to reset the nodes receive handler in case of an error. The host should still
enforce a 5 second message response timeout so that it can detect and handle errors.