Block description

STOTG04ES

16/26

The RCV signal is active in the VP_VM mode only. Its output driver is controlled by the OE_TP_INT/

signal. Operating modes are described below. The meanings of the DAT_VP and SE0_VM signals

depend on the mode of operation. Both of these signals can be bidirectional or unidirectional. The

direction is controlled by bidi_en Bit of Control Register 3 (described later). When these signals are

bidirectional, the direction is controlled by the OE_TP_INT/ signal (see Tables 11 and 12).

The actual mode of operation is controlled by the dat_se0 Bit of Control Register 1 (see Tables 11 and 12)

Table 11.

DAT_SE0 (dat_se0 = 1)

Table 12.

VP_VM (dat_se0 = 0)

* State of the OE_TP_INT/ signal.

In the USB mode of operation it is necessary to control the rise and fall times of the transmission driver.

These times are different for low-speed and full-speed USB settings. Selection of actual USB speed can

be done using the bit speed of Control Register 1 or/and the SPEED pin (see table 13).

Table 13.

USB Speed Selection

6.7.3

UART Mode

The actual mode of operation is selectable by the transp_en and uart_en Bits of Control Register 1 (see

table 14).

Table 14.

Transceiver modes

(1) In reality, it is not possible to set both these bits at the same time. In this case, only uart_en bit will remain set.

In the UART mode it is possible to select driver direction on both the D+ and D– pins. The selection is

done using the bdir[1] and bdir[0] Bits of Control Register 3 (see table 15).

bidi_en

OE/*

DAT_VP

SE0_VM

1

0

Differential driver input

SE0 driver input

1

Differential receiver output

SE0 detector output

0

X

Differential driver input

SE0 driver input

bidi_en

OE/*

DAT_VP

SE0_VM

1

0

D+ driver input

D- driver input

1

D+ receiver output

D- receiver output

0

X

D+ driver input

D- driver input

speed bit

SPEED Pin

USB Mode

0X

low-speed

X0

1

1

full-speed

transp_en

uart_en

STOTG04 Mode

00

USB

01

UART

1

0

FORBIDDEN

11

UART (1)