9–36
Chapter 9: Using User Flash Memory in MAX II Devices
Software Support for UFM Block
Figure 9–39.
Page 3 altufm MegaWizard Plug-In Manager (SPI)
1
The UFM block’s internal oscillator is always running when the altufm_spi
megafunction is instantiated for read/write interface. The UFM block’s internal
oscillator is disabled when the
altufm_spi
megafunction is instantiated for read
only interface.
Parallel Interface
This interface allows for parallel communication between the UFM block and outside
logic. Once the
READ
request,
WRITE
request, or
ERASE
request is asserted (active low
assertion), the outside logic or device (such as a microcontroller) are free to continue
their operation while the data in the UFM is retrieved, written, or erased. During this
time, the
nBUSY
signal is driven “low” to indicate that it is not available to respond to
any further request. After the operation is complete, the
nBUSY
signal is brought back
to “high” to indicate that it is now available to service a new request. If it was the
Read request, the
DATA_VALID
is driven “high” to indicate that the data at the
DO
port
is the valid data from the last read address.
Asserting
READ, WRITE,
and
ERASE
at the same time is not allowed. Multiple requests
are ignored and nothing is read from, written to, or erased in the UFM block. There is
no support for sequential read and page write in the parallel interface. For both the
read only and the read/write modes of the parallel interface,
OSC_ENA
is always
asserted, enabling the internal oscillator.
summarizes the parallel interface
pins and functions.
ALTERA [ ALTERA CORPORATION ]
