
C8051F340/1/2/3/4/5/6/7
SFR Definition 16.1. USB0XCN: USB0 Transceiver Control
R/W  | R/W  | R/W  | R/W  | R/W  | R  | R  | R  | Reset Value  | 
PREN | PHYEN | SPEED | PHYTST1 | PHYTST0 | DFREC | Dp  | Dn  | 
Bit7  | Bit6  | Bit5  | Bit4  | Bit3  | Bit2  | Bit1  | Bit0  | 
00000000
SFR Address:
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  | 0xD7  | 
Bit7:  | PREN: Internal   | 
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  | The location of the   | |||||
  | 0: Internal   | |||||
  | 1: Internal   | |||||
  | work).  | 
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Bit6:  | PHYEN: Physical Layer Enable  | 
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  | This bit enables/disables the USB0 physical layer transceiver.  | |||||
  | 0: Transceiver disabled (suspend).  | 
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  | 1: Transceiver enabled (normal).  | 
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Bit5:  | SPEED: USB0 Speed Select  | 
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  | This bit selects the USB0 speed.  | 
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  | 0: USB0 operates as a Low Speed device. If enabled, the internal   | |||||
  | on the D– line.  | 
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  | 1: USB0 operates as a Full Speed device. If enabled, the internal   | |||||
  | the D+ line.  | 
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  | These bits can be used to test the USB0 transceiver.  | 
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  | PHYTST[1:0] | Mode | 
  | D+  | D–  | 
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  | 00b  | Mode 0: Normal   | 
  | X  | X  | 
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  | 01b  | Mode 1: Differential ‘1’ Forced  | 
  | 1  | 0  | 
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  | 10b  | Mode 2: Differential ‘0’ Forced  | 
  | 0  | 1  | 
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  | 11b  | Mode 3:   | 
  | 0  | 0  | 
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Bit2:  | DFREC: Differential Receiver  | 
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  | The state of this bit indicates the current differential value present on the D+ and D– lines  | |||||
  | when PHYEN = ‘1’.  | 
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  | 0: Differential ‘0’ signaling on the bus.  | 
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  | 1: Differential ‘1’ signaling on the bus.  | 
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Bit1:  | Dp: D+ Signal Status  | 
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  | This bit indicates the current logic level of the D+ pin.  | 
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  | 0: D+ signal currently at logic 0.  | 
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  | 1: D+ signal currently at logic 1.  | 
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Bit0:  | Dn: D- Signal Status  | 
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  | This bit indicates the current logic level of the D– pin.  | 
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0: D– signal currently at logic 0.
1: D– signal currently at logic 1.
Rev. 0.5  | 165  |