7–36
Chapter 7: User Flash Memory in MAX V Devices
Software Support for UFM Block
Parallel Interface
This interface allows for parallel communication between the UFM block and outside
logic. After the READrequest, WRITErequest, or ERASErequest is asserted (active low
assertion), the outside logic or device (such as a microcontroller) can continue its
operation while the data in the UFM is retrieved, written, or erased. During this time,
the nBUSYsignal is driven “low” to indicate that it is not available to respond to any
further request. After the operation is complete, the nBUSYsignal 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_VALIDis driven “high” to indicate that the data at the DOport is the
valid data from the last read address.
Asserting READ WRITE, and ERASEat 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_ENAis always
asserted, enabling the internal oscillator. Table 7–15 lists the parallel interface pins and
functions.
Table 7–15. Parallel Interface Signals
Pin
Description
16-bit data Input
Function
Receive 16-bit data in parallel. You can select an optional width of 3 to
16 bits using the ALTUFM megafunction.
DI[15..0]
Transmit 16-bit data in parallel. You can select an optional width of 3 to
16 bits using the ALTUFM megafunction.
DO[15..0]
16-bit data Output
Address Register
Operation sequence refers to the data that is pointed to by the address
register. You can determine the address bus width using the ALTUFM
megafunction.
ADDR[8..0]
nREAD
READInstruction Signal
WRITEInstruction Signal
Initiates a read sequence.
Initiates a write sequence.
nWRITE
Initiates a SECTOR-ERASE sequence indicated by the MSB of the
ADDR[]port.
nERASE
ERASEInstruction Signal
BUSYSignal
Driven low to notify that it is not available to respond to any further
request.
nBUSY
Driven high to indicate that the data at the DOport is the valid data from
the last read address for read request.
DATA_VALID
Data Valid
Even though the ALTUFM megafunction allows you to select the address widths
range from 3 bits to 9 bits, the UFM block always expects a full 9 bits for the width of
the address register. Therefore, the ALTUFM megafunction will always pad the
remaining LSBs of the address register with '0's if the register width selected is less
than 9 bits. The address register will point to sector 0 if the address received at the
address register starts with a '0'. The address register will point to sector 1 if the
address received starts with a '1'.
Even though you can select an optional data register width of 3 to 16 bits using the
ALTUFM megafunction, the UFM block always expects full 16 bits width for the data
register. Reading from the data register always proceeds from MSB to LSB. The
ALTUFM megafunction always pads the remaining LSBs of the data register with 1s if
the user selects a data width of less than 16-bits.
MAX V Device Handbook
January 2011 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
