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ISP1581

Universal serial bus 2.0 high-speed interface device

Philips Electronics 

Philips Semiconductors

ISP1581

USB 2.0 HS interface device

9397 750 09665

Product data

7.4 Voltage regulators

Two 5 V to 3.3 V voltage regulators are integrated on-chip to separately supply the

analog transceiver and the internal logic. The output of these voltage regulators are

termed as VCCA(3.3) and VCC(3.3) to distinguish them as being used for the analog

block and the digital block, respectively. The pin VCCA(3.3) is also used to supply an

external 1.5 kΩ pull-up resistor on the D+ line.

Remark: Pins VCCA(3.3) and VCC(3.3) cannot be used to supply external devices.

7.5 Memory Management Unit (MMU) and integrated RAM

The MMU and the integrated RAM provide the conversion between the USB speed

(full speed: 12 Mbit/s, high speed: 480 Mbit/s) and the Microcontroller Handler or the

DMA Handler. The data from the USB Bus is stored in the integrated RAM, which is

cleared only when the microcontroller has read/written all data from/to the

corresponding endpoint buffer or when the DMA Handler has read/written all data

from/to the endpoint buffer. The endpoint buffer can also be cleared forcibly by setting

the CLBUF bit in the control function register. A total of 8 kbytes RAM is available for

buffering.

7.6 SoftConnect

The connection to the USB is established by pulling the D+ line (for full-speed

devices) HIGH through a 1.5 kΩ pull-up resistor. In the ISP1581 an external 1.5 kΩ

pull-up resistor must be connected between pins RPU and VCCA(3.3). The RPU pin

connects the pull-up resistor to the D+ line, when bit SOFTCT in the Mode register is

set (see Table 7). After a hardware reset the pull-up resistor is disconnected by

default (SOFTCT = 0). Bit SOFTCT remains unchanged by a USB bus reset.

7.7 Microcontroller/Processor Interface and

Microcontroller/Processor Handler

The Microcontroller Interface allows direct interfacing to most microcontrollers. The

interface is configured at power-up via inputs BUS_CONF, MODE1 and MODE0.

When BUS_CONF is set to logic 1, the Microcontroller Interface switches to the

Generic Processor mode in which AD[7:0] is the 8-bit address bus and DATA[15:0]

is the separate 16-bit data bus. If BUS_CONF is made logic 0, the interface is in the

Split Bus mode, where AD[7:0] is the local microprocessor bus (multiplexed

address/data) and DATA[15:0] is solely used as the DMA bus.

If pin MODE0 is set to logic 1, pins RD and WR are the read and write strobes (8051

style). If pin MODE0 is logic 0, pins R/W and DS pins represent the direction and data

strobe (Motorola style).

When pin MODE1 is made logic 0, ALE is used to latch the multiplexed address on

pins AD[7:0]. If pin MODE1 is set to logic 1, A0 is used to indicate address or data.

Pin MODE1 is only used in Split Bus mode: in Generic Processor mode it must be

tied to VCC(5.0) (logic 1).

The Microcontroller Handler allows the external microcontroller to access the register

set in the Philips SIE as well as the DMA Handler. The initialization of the DMA

configuration is done via the Microcontroller Handler.

Rev. 04 — 18 July 2002

© Koninklijke Philips Electronics N.V. 2002. All rights reserved.

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