CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
Preliminary User’s Manual U19014EJ1V0UD
316
(31) UF0 mode status register (UF0MODS)
This register indicates the configuration status.
This register is read-only, in 8-bit units.
0
UF0MODS
CDCGD
5
0
MPACK
3
DFLT
2
CONF
1
0
0
Address
FF2FH
After reset
00H
0
4
6
7
Bit position
Bit name
Function
6
CDCGD
This bit specifies whether CPUDEC processing is performed for the GET_DESCRIPTOR
Configuration request.
1: Forcibly change the GET_DESCRIPTOR Configuration request to CPUDEC
processing.
0: Automatically process the GET_DESCRIPTOR Configuration request (default
value).
4
MPACK
This bit indicates the transmit packet size of Endpoint0.
1: Transmit a packet of other than 8 bytes.
0: Transmit a packet of 8 bytes (default value).
This bit is automatically set to 1 by hardware after the GET_DESCRIPTOR Device
request has been processed (on normal completion of the status stage). It is not cleared
to 0 until the USBF has been reset (it is not cleared to 0 by Bus Reset).
If this bit is not set to 1, the hardware transfers only the automatically-executed request
in 8-byte units. Therefore, even if data of more than 8 bytes is sent by the OUT token to
be processed by FW before completion of the GET_DESCRIPTOR Device request, the
data is correctly received.
This bit is ignored if the size of Endpoint0 is 8 bytes.
3
DFLT
This bit indicates the default status (DFLT bit = 1).
1: Enables response.
0: Disables response (always no response) (default value).
This bit is automatically set to 1 by Bus Reset. The transaction for all the endpoints is
not responded to until this bit is set to 1.
2
CONF
This bit indicates whether the SET_CONFIGURATION request has been completed.
1: SET_CONFIGURATION request has been completed.
0: SET_CONFIGURATION request has not been completed (default value).
This bit is set to 1 when Configuration value = 1 is received by the
SET_CONFIGURATION request.
Unless this bit is set to 1, access to an endpoint other than Endpoint0 is ignored.
This bit is cleared to 0 when Configuration value = 0 is received by the
SET_CONFIGURATION request. It is also cleared to 0 when Bus Reset is detected.
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