Get Config Request; Get Descriptor Request - Philips PDIUSBD12 Firmware Programming Manual

Interconnectivity Page 17 of 22
Firmware Programming Guide for PDIUSBD12

7.4 Get Config Request

In the Get_config request, the MCU will have to return the current configuration value. Firstly, the MCU will
determine whether the device has been configured or not. If the device is not configured, it returns a zero to the
host, or else it returns a one if the device is configured.
Get Config
Has Device been
"Configuration"?
Sent " 0 " to host Sent " 1" to host
End Get
Config

7.5 Get Descriptor Request

For the Get Descriptor request, MCU must return the specific descriptor if the descriptor exists. Firstly, MCU
will determine whether the descriptor type request is for the device or the configuration. It will then send the
first 16 bytes of device descriptor if the descriptor type is for device. The reason for controlling the size of
returning bytes is due to the fact that the control buffer has only 16 bytes of memory. MCU will need to set a
register to indicate the location of the transmitted size.
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