C8051F34A-GMR Silicon Labs, C8051F34A-GMR Datasheet - Page 161

• Manufacturer Part Number: C8051F34A-GMR
• Description: 8-bit Microcontrollers - MCU 48 MIPS 64KB 10ADC
• Manufacturer: Silicon Labs

Specifications of C8051F34A-GMR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

Bit7:
Bit6:
Bit5:
Bits4–3: PHYTST1–0: Physical Layer Test
Bit2:
Bit1:
Bit0:
PREN
R/W
Bit7
PREN: Internal Pull-up Resistor Enable
The location of the pull-up resistor (D+ or D–) is determined by the SPEED bit.
0: Internal pull-up resistor disabled (device effectively detached from the USB network).
1: Internal pull-up resistor enabled when VBUS is present (device attached to the USB net-
work).
PHYEN: Physical Layer Enable
This bit enables/disables the USB0 physical layer transceiver.
0: Transceiver disabled (suspend).
1: Transceiver enabled (normal).
SPEED: USB0 Speed Select
This bit selects the USB0 speed.
0: USB0 operates as a Low Speed device. If enabled, the internal pull-up resistor appears
on the D– line.
1: USB0 operates as a Full Speed device. If enabled, the internal pull-up resistor appears on
the D+ line.
These bits can be used to test the USB0 transceiver.
DFREC: Differential Receiver
The state of this bit indicates the current differential value present on the D+ and D– lines
when PHYEN = ‘1’.
0: Differential ‘0’ signaling on the bus.
1: Differential ‘1’ signaling on the bus.
Dp: D+ Signal Status
This bit indicates the current logic level of the D+ pin.
0: D+ signal currently at logic 0.
1: D+ signal currently at logic 1.
Dn: D- Signal Status
This bit indicates the current logic level of the D– pin.
0: D– signal currently at logic 0.
1: D– signal currently at logic 1.
PHYTST[1:0]
PHYEN
SFR Definition 16.1. USB0XCN: USB0 Transceiver Control
R/W
Bit6
00b
01b
10b
11b
SPEED
R/W
Bit5
Mode 0: Normal (non-test mode)
Mode 1: Differential ‘1’ Forced
Mode 2: Differential ‘0’ Forced
Mode 3: Single-Ended ‘0’ Forced
C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D
PHYTST1 PHYTST0 DFREC
R/W
Bit4
Mode
Rev. 1.3
R/W
Bit3
Bit2
R
D+
X
1
0
0
D–
X
0
1
0
Bit1
Dp
R
Bit0
Dn
R
SFR Address:
00000000
Reset Value
0xD7
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