3–14
Chapter 3: Serial Configuration Devices (EPCS1, EPCS4, EPCS16, EPCS64, and EPCS128) Data Sheet
Serial Configuration Device Memory Access
Table 3–6.
Address Range for Sectors in EPCS4 (Part 2 of 2)
Address Range (Byte Addresses in HEX)
Sector
1
0
Start
H'10000
H'00000
End
H'1FFFF
H'0FFFF
Table 3–7.
Address Range for Sectors in EPCS1
Address Range (Byte Addresses in HEX)
Sector
3
2
1
0
Start
H'18000
H'10000
H'08000
H'00000
End
H'1FFFF
H'17FFF
H'0FFFF
H'07FFF
Operation Codes
This section describes the operations that can be used to access the memory in serial
configuration devices. The
DATA, DCLK, ASDI,
and
nCS
signals access the memory in
serial configuration devices. All serial configuration device operation codes,
addresses and data are shifted in and out of the device serially, with the most
significant bit (MSB) first.
The device samples the active serial data input on the first rising edge of the
DCLK
after the active low chip select (nCS) input signal is driven low. Shift the operation
code (MSB first) serially into the serial configuration device through the active serial
data input (ASDI) pin. Each operation code bit is latched into the serial configuration
device on the rising edge of the
DCLK.
Different operations require a different sequence of inputs. While executing an
operation, you must shift in the desired operation code, followed by the address
bytes, data bytes, both, or neither. The device must drive
nCS
high after the last bit of
the operation sequence is shifted in.
lists the operation sequence for every
operation supported by the serial configuration devices.
For the read byte, read status, and read silicon ID operations, the shifted-in operation
sequence is followed by data shifted out on the
DATA
pin. You can drive the
nCS
pin
high after any bit of the data-out sequence is shifted out.
For the write byte, erase bulk, erase sector, write enable, write disable, and write
status operations, drive the
nCS
pin high exactly at a byte boundary (drive the
nCS
pin high a multiple of eight clock pulses after the
nCS
pin is driven low); otherwise,
the operation is rejected and is not executed.
All attempts to access the memory contents while a write or erase cycle is in progress
will not be granted, and the write or erase cycle will continue unaffected.
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