OXCF950 datasheet(11/66 Pages) OXFORD

11 / 66 page

DS-0027 Feb 06

External—Free Release

Page 11 of 66

OXCF950 rev B DATA SHEET

OXFORD SEMICONDUCTOR, INC.

CONFIGURATION & OPERATION

4.1

Mode Selection

The OXCF950 has four default modes of operation, as

shown in the table below.

MODE pin EE_DI pin

Operation

‘Generic’ Normal mode

with 3 address bits

decoded for I/O

16C950 mode

(standard local bus type

UART)

‘1’ or to external

EEPROM

‘Normal’ mode with 4

address bits decoded

for I/O

‘1’ or to external

EEPROM

‘Local Bus’ mode with 4

address bits decoded

for I/O

Table 2: Default Modes of Operation

4.1.1

Generic Mode

Generic Mode is compatible with PCMCIA and CF host

systems. It is the same as ‘Normal’ mode, except that

when I/O accesses take place, only the bottom 3 bits of the

address range are decoded. Similarly the Card Information

Structure indicates an I/O range of 8 locations. This mode

allows generic drivers to locate the UART on a default 8-

byte boundary. In this mode access to the configuration

registers is performed via paging. Generic mode address

decoding can also be selected by EEPROM configuration.

4.1.2

16C950 Mode

This mode is provided for non PCMCIA/CF applications. In

this mode all the PCMCIA/CF decoding, CIS and EEPROM

sections of the design are bypassed and the CF950 acts as

a local-bus style device. To implement this mode -

REG#, EE_DI should be tied to GND,

OE#, WE#, MODE should be tied to VDD.

The user can use A3 to access configuration registers to

allow control of MIO pins and the clock divider. For most

applications, however, A3, MIO1 and MIO0 should also be

tied to GND.

CE1#, IORD#, IOW# and A[2..0] then become the local bus

chip-select and read, write, address access controls.

IREQ# becomes an active-high interrupt output, and

IOIS16# becomes an active-low interrupt output.

4.1.3

Normal/Local Bus Modes

These modes are identical to the previous CF950 modes of

operation. They are suitable for PCMCIA/CF host systems.

4.2

PCMCIA/CF Operation

PCMCIA and CF host systems allow for hot insertion of

cards.

Once a card has been inserted into a host system, the host

system will configure it. The PCMCIA standard defines two

card detect pins, that allow the host to be notified when a

card is inserted or removed.

By default the device will power up in either Normal or

Local Bus mode, depending on the mode pin (and the

EE_DI pin for ‘Generic’ mode). The difference between

these two modes is given in the following table. Note that

the Local Bus mode is not suitable for CF systems.

Normal Mode (MODE=0)

Local Bus Mode (MODE=1)

Address bus is 8 bits wide.

Address bus is 4 bits wide.

Indirect access is not used.

Indirect access is used.

No external local bus.

External local bus supported.

Table 3: Differences between Normal & Local Bus Mode

The host system will wait for the READY# signal to be

active before reading the Card Information Structure, given

in attribute memory within the device. By reading this tuple

information, the host system is able to identify the device

type and the necessary resources requested by the device.

The host system will then load the device-driver software

according to this information and will configure the IO,

memory and interrupt resources. After determining that the

device is a memory and IO type device the host will enable

it’s IO mode by writing to the device’s Configuration

Options Register in attribute memory space.

Device

drivers can then access the functions at the assigned

addresses.

A set of local configuration registers have been provided

that can be used to control the device’s characteristics

(such as interrupt handling) and report internal functional

status. These registers can be accessed in IO space,

utilising the same IO space as the local bus (Local Bus

mode only) and are situated above the UART registers.

These local registers can be set up by device drivers or

from the optional EEPROM. In generic mode, the

OXCF950 датащи(PDF) 11 Page - Oxford Semiconductor

OXCF950 датащи(HTML) 11 Page - Oxford Semiconductor

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66

датащи скачать

ссылки URL