ISP1160 Просмотр технического описания (PDF) - Philips Electronics

Номер в каталоге

Компоненты Описание

Список матч

ISP1160

Embedded Universal Serial Bus Host Controller

Philips Electronics 

Philips Semiconductors

ISP1160

Embedded USB Host Controller

8.3 Control registers access by PIO mode

8.3.1 I/O port addressing

Table 3 shows the ISP1160’s I/O port addressing. Complete decoding of the I/O port

address should include the chip select signal CS_N and the address line A0.

However, the direction of access of I/O ports is controlled by the RD_N and

WR_N signals. When RD_N is LOW, the microprocessor reads data from the

ISP1160’s data port. When WR_N is LOW, the microprocessor writes a command to

the command port, or writes data to the data port.

Table 3: I/O port addressing

Port CS_N A0

Access Data bus width

(bits)

0

0

0

R/W 16

1

0

1

W

16

Description

HC data port

HC command port

Figure 5 illustrates how an external microprocessor accesses the ISP1160’s internal

control registers.

9397 750 11371

Product data

CMD/DATA

SWITCH

Host bus I/F

1

command port

data port

0

A0

...

Commands

Command register

Control registers

When A0 = 0, microprocessor accesses the data port.

When A0 = 1, microprocessor accesses the command port.

Fig 5. Access to internal control registers.

004aaa075

8.3.2 Register access phases

The ISP1160’s register structure is a command-data register pair structure. A

complete register access cycle comprises a command phase followed by a data

phase. The command (also known as the index of a register) points the ISP1160 to

the next register to be accessed. A command is 8 bits long. On a microprocessor’s

16-bit data bus, a command occupies the lower byte, with the upper byte filled with

zeros.

Figure 6 shows a complete 16-bit register access cycle for the ISP1160. The

microprocessor writes a command code to the command port, and then reads from or

writes the data word to the data port. Take the example of a microprocessor

attempting to read the ISP1160’s ID, which is saved in the HC’s HcChipID register

(index 27H, read only). The 16-bit register access cycle is therefore:

1. The microprocessor writes the command code of 27H (0027H in 16-bit width) to

the HC command port

2. The microprocessor reads the data word of the chip’s ID from the HC data port.

Rev. 04 — 04 July 2003

© Koninklijke Philips Electronics N.V. 2003. All rights reserved.

10 of 88

Share Link: