Card Detection - Analog Devices ADSP-BF506F Hardware Reference Manual

In order to stop the signals from floating when no card is inserted or dur-
ing times when all card drivers are in a high-impedance mode, various
pull-up and pull-down resistor configurations can be enabled on the
signals. The
RSI_DATAx
ister (RSI_CONFIG)" on page
• Enable or disable a pull-down resistor on the
• Enable or disable a pull-up resistor on the
• Enable or disable pull-up resistors on the
RSI_DATA4
signal

Card Detection

The RSI allows for software to detect when a card is inserted into its slot.
There are a number of ways that this card detection can be performed.
SD and SDIO cards use an internal pull-up resistor on the
as a card detect signal to indicate to the host that a card is present. In
order to use the
pull-down resistor should be added to the pin in order to pull the pin low
during the time a card is not inserted. When a card is inserted into the
slot, a rising edge is detected on
set within the
fied, the
SD_CARD_DET
pull-up resistor within the SD card should be disabled by issuing the
SET_CLR_CARD_DETECT

When using the
nal pull-down resistor, do not enable the internal pull-up resistor
by setting
The recommended method of detecting the insertion of a card is to use
the card detect feature that is made available through most sockets.
ADSP-BF50x Blackfin Processor Hardware Reference
RSI_CONFIG
21-78) allows for the following options:
, through
RSI_DATA2
signal for card detection, an external
RSI_DATA3
RSI_DATA3
register. Once the card has been correctly identi-
RSI_ESTAT
interrupt should be cleared and disabled then the
command.
RSI_DATA3
.
PU_DAT3
Removable Storage Interface
register (see "RSI Configuration Reg-
RSI_DATA3
RSI_DATA3
RSI_DATA7
signals and the
RSI_DATA0
by the RSI and
signal for card detection with an exter-
signal
signal
through
RSI_CMD
line
RSI_DATA3
is
SD_CARD_DET
21-11