7–10
Chapter 7: User Flash Memory in MAX V Devices
UFM Operating Modes
Program
To program or write to the UFM, you must first perform a sequence to load the
reference address into the address register. DRSHFTmust then be asserted high to load
the data serially into the data register starting with the MSB. Loading an address into
the address register and loading data into the data register can be done concurrently.
After the 16 bits of data have been successfully shifted into the data register, the
PROGRAMsignal must be asserted high to start writing to the UFM. On the rising edge,
the data currently in the data register is written to the location currently in the address
register. The BUSYsignal is asserted until the program sequence is completed. The data
and address register should not be modified until the BUSYsignal is de-asserted, or the
flash content will be corrupted. The PROGRAMsignal is ignored if the BUSYsignal is
asserted. When the PROGRAMsignal is applied at exactly the same time as the ERASE
signal, the behavior is undefined and the flash content is corrupted. Figure 7–7 shows
the UFM waveforms during program mode.
Figure 7–7. UFM Program Waveforms
9 Address Bits
tACLK
ARSHFT
ARCLK
tAH
tASU
tADH
ARDin
tADS
16 Data Bits
tDCLK
DRSHFT
DRCLK
tDSH
tDSS
DRDin
tDDH
tDDS
DRDout
OSC_ENA
PROGRAM
ERASE
tOSCH
tOSCS
tPB
tBP
BUSY
tPPMX
MAX V Device Handbook
January 2011 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
