Rainbow Electronics AT89C5122 - Manual (Page 120)

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AT8xC5122/23
4202E–SCR–06/06
Reset Value = 0000 0000b
Reset Value = 1000 0000b when UEPNUM = 0
Reset Value = 0000 0000b otherwise
Table 68. USB Endpoint Number - UEPNUM (S:C7h)
7 6 5 4 3 2 1 0
- - - - EPNUM3 EPNUM2 EPNUM1 EPNUM0
Bit Number Bit Mnemonic Description
7 - 4 -
Reserved
The value read from these bits is always 0. Do not change these bits.
3 - 0 EPNUM[3:0]
Endpoint Number
Set this field with the number of the endpoint which should be accessed when reading or writing to, USB Byte
Count Register X (X=EPNUM set in UEPNUM Register) - UBYCTX (S:E2h) or USB Endpoint X Control Register -
UEPCONX (S:D4h). This value can be 0, 1, 2, 3, 4, 5 or 6.
Table 69. USB Endpoint X Control Register - UEPCONX (S:D4h)
7 6 5 4 3 2 1 0
EPEN NAKIEN NAKOUT NAKIN DTGL EPDIR EPTYPE1 EPTYPE0
Bit Number Bit Mnemonic Description
7 EPEN
Endpoint Enable
Set this bit to enable the endpoint according to the device configuration. Endpoint 0 will always be enabled after
a hardware or USB bus reset and participate in the device configuration.
Clear this bit to disable the endpoint according to the device configuration.
6 NAKIEN
NAK Interrupt Enable
Set this bit to enable NAKIN and NAKOUT Interrupt.
Clear this bit to disable NAKIN and NAKOUT Interrupt.
5 NAKOUT
NAK OUT Sent
This bit is set by hardware when the a NAK handshake is sent by the USB controller to an OUT request from
the Host. This generates an interrupt if the NAKIEN bit is set.
This bit shall be cleared by software.
4 NAKIN
NAK IN Sent
This bit is set by hardware when the a NAK handshake is sent by the USB controller to an IN request from the
Host. This generates an interrupt if the NAKIEN bit is set.
This bit shall be cleared by software.
3 DTGL
Data Toggle (Read-only)
This bit is set by hardware when a valid DATA0 packet is received and accepted.
This bit is cleared by hardware when a valid DATA1 packet is received and accepted.
2 EPDIR
Endpoint Direction
Set this bit to configure IN direction for Bulk, Interrupt and Isochronous endpoints.
Clear this bit to configure OUT direction for Bulk, Interrupt and Isochronous endpoints.
This bit has no effect for Control endpoints.
1-0 EPTYPE[1:0]
Endpoint Type
Set this field according to the endpoint configuration (Endpoint 0 will always be configured as control):
00Control endpoint
01Isochronous endpoint
10Bulk endpoint
11Interrupt endpoint