Serial Configuration Devices (EPCS1, EPCS4, EPCS16 & EPCS64) Data Sheet
The erase sector operation is implemented by first driving nCSlow, then
shifting in the erase sector operation code and the three address bytes of
the chosen sector on the ASDIpin. The three address bytes for the erase
sector operation can be any address inside the specified sector. (See
Tables 4–6 and 4–7 for sector address range information.) Drive nCShigh
after the eighth bit of the erase sector operation code has been latched in.
Figure 4–15 shows the timing diagram.
Immediately after the device drives nCShigh, the self-timed erase sector
cycle is initiated. The self-timed erase sector cycle usually takes 2 s for
EPCS1 and EPCS4 devices and is guaranteed to be less than 3 s for both
serial configuration devices. You must account for this amount of delay
before the memory contents can be accessed. Alternatively, you can check
the write in progress bit in the status register by executing the read status
operation while the erase cycle is in progress. The write in progress bit is
1during the self-timed erase cycle and is 0when it is complete. The write
enable latch bit in the status register is reset to 0before the erase cycle is
complete.
Figure 4–15. Erase Sector Operation Timing Diagram
nCS
DCLK
ASDI
0
1
2
3
4
5
6
7
8
9
28 29 30 31
Operation Code
24-Bit Address
23 22
3
2
1
0
MSB
This section describes the power modes, power-on reset (POR) delay,
error detection, and initial programming state of serial configuration
devices.
Power &
Operation
Power Mode
Serial configuration devices support active power and standby power
modes. When nCSis low, the device is enabled and is in active power
mode. The FPGA is configured while in active power mode. When nCSis
high, the device is disabled but could remain in active power mode until
all internal cycles have completed (such as write or erase operations). The
serial configuration device then goes into stand-by power mode. The ICC1
Altera Corporation
July 2004
Core Version a.b.c variable
4–23
Configuration Handbook, Volume 2
ALTERA [ ALTERA CORPORATION ]
