Signal
Name
Alternate
Function
Type Description
Command Latch Enable Signal
NFCLE
NFRE
NFWE
O
O
O
-
-
-
Asserted high during command write cycle.
Read Enable Signal
Read signal asserted low during NF/SMC read operation.
Write Enable Signal
Write signal asserted low during NF/SMC write operation.
Nand Flash 0 Chip Enable
NFCE0
NFCE1
O
O
-
NFCE0 is active low and is asserted by the nand flash controller each
time it makes access to the device 0.
Nand Flash 1 Chip Enable
NFCE1 is active low and is asserted by the nand flash controller each
time it makes access to the selected device.
SMLCK
I
SmartMediaCard/xD-Picture Card Write Lock Signal
P4.4
SMLCK is the card write protected input. A low level on this pin
indicates the card is write protected.
Note:
When used as SMLCK input, pad has internal pull-up.
NFCE2
SMINS
O
I
Nand Flash 2 Chip Enable
NFCE2 is active low and is asserted by the nand flash controller each
time it makes access to the selected device.
SmartMediaCard/xD-Picture Card Insertion Signal
P4.5
SMINS is the card presence signal. A low level on this input indicates
the card is present in its slot.
Note:
When used as SMINS input, pad has internal pull-up.
NFCE3
SMCE
Nand Flash 3 Chip Enable
NFCE3 is active low and is asserted by the nand flash controller each
time it makes access to the selected device.
O
O
P4.6
SmartMediaCard/xD-Picture Card Chip Enable
SMCE is active low and is asserted by the nand flash controller each
time it makes access to the card.
Write Protect Signal
NFWP is the Nand Flash / SmartMediaCard/xD-Picture Card write
protect signal. This signal is active low and is set to low during reset in
order to protect the memory against parasitic writes.
NFWP
-
USB Controller
Table 7. USB Controller Signal Description
Signal
Name
Alternate
Function
Type Description
DPF
I/O USB Full Speed Positive Data Upstream Port
I/O USB Full Speed Minus Data Upstream Port
I/O USB High Speed Plus Data Upstream Port
I/O USB High Speed Minus Data Upstream Port
USB VBUS Control line
-
-
-
-
DMF
DPH
DMH
UVCON
O
UVCON is used to control the external VBUS power supply ON or OFF.
Note: This output is requested for OTG mode.
P3.6
10
AT85C51SND3Bx
7632A–MP3–03/06
ATMEL [ ATMEL ]
