9–28
Chapter 9: Using User Flash Memory in MAX II Devices
Software Support for UFM Block
Figure 9–27 shows the READoperation sequence for Base mode.
Figure 9–27. READ Operation for Base Mode
nCS
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 23
SCK
SI
8-bit
Instruction
8-bit
Instruction
03H
MSB
MSB
High Impendance
SO
8-bit Data Out 1
MSB
8-bit Data Out 2
MSB
WRITE
WRITEis the instruction for data transmission, where the data is written to the UFM
block. The targeted location in the UFM block that will be written must be in the
erased state (FFFFH) before initiating a WRITEoperation. When data transfer is taking
place, the MSB is always the first bit to be transmitted or received. nCSmust be driven
high before the instruction is executed internally. You may poll the nRDYbit in the
software status register for the completion of the internal self-timed WRITEcycle. For
SPI Extended mode, the WRITEoperation is always done through the following
sequence, as shown in Figure 9–28:
1. nCSis pulled low to indicate the start of transmission.
2. An 8-bit WRITEopcode (00000010) is received from the master device. If internal
programming is in progress, the WRITEoperation is ignored and not accepted.
3. A 16-bit address is received from the master device. The LSB of the address will be
received last. As the UFM block can take only nine bits of address maximum, the
first seven address bits received are discarded.
4. A check is carried out on the status register (see Table 9–11) to determine if the
WRITEoperation has been enabled, and the address is outside of the protected
region; otherwise, Step 5 is bypassed.
5. One word (16 bits) of data is transmitted to the slave device through SI.
6. nCSis pulled back to high to indicate the end of transmission.
For SPI Base mode, the WRITEoperation is always performed through the following
sequence in SPI:
1. nCSis pulled low to indicate the start of transmission.
2. An 8-bit WRITEopcode (00000010) is received. If the internal programming is in
progress, the WRITEoperation is ignored and not accepted.
3. An 8-bit address is received. A check is carried out on the status register (see
Table 9–11) to determine if the WRITEoperation has been enabled, and the address
is outside of the protected region; otherwise, Step 4 is skipped.
MAX II Device Handbook
© October 2008 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
