EPCS4 datasheet(22/32 Pages) ALTERA

22 / 32 page

4–22

Core Version a.b.c variable

Altera Corporation

Configuration Handbook, Volume 2

July 2004

Serial Configuration Device Memory Access

Erase Bulk Operation

The erase bulk operation code is

b'1100 0111, with the MSB listed first.

The erase bulk operation sets all memory bits to

1 or 0xFF. Similar to the

write bytes operation, the write enable operation must be executed prior

to the erase bulk operation so that the write enable latch bit in the status

Designers implement the erase bulk operation by driving

nCS low and

then shifting in the erase bulk operation code on the

ASDI pin. nCS must

be driven high after the eighth bit of the erase bulk operation code has

been latched in. Figure 4–14 shows the timing diagram.

The device initiates the self-timed erase bulk cycle immediately after

nCS

is driven high. The self-timed erase bulk cycle usually takes 5 s for EPCS4

devices (guaranteed to be less than 10 s) or 3 s for EPCS1 devices

(guaranteed to be less than 6 s). See tEB in Table 4–12. Designers must

account for this delay before accessing the memory contents.

Alternatively, designers can check the write in progress bit in the status

cycle is in progress. The write in progress bit is

1 during the self-timed

erase cycle and is

0 when it is complete. The write enable latch bit in the

status register is reset to

0 before the erase cycle is complete.

Figure 4–14. Erase Bulk Operation Timing Diagram

Erase Sector Operation

The erase sector operation code is

b'1101 1000, with the MSB listed

first. The erase sector operation allows the user to erase a certain sector in

the serial configuration device by setting all bits inside the sector to

1 or

0xFF. This operation is useful for users who access the unused sectors as

general purpose memory in their applications.

The write enable operation must be executed prior to the erase sector

operation so that the write enable latch bit in the status register is set to

nCS

DCLK

ASDI

01234567

Operation Code

EPCS4 Datasheet(PDF) 22 Page - Altera Corporation

EPCS4 Datasheet(HTML) 22 Page - Altera Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Datasheet Download

Link URL