PRELIMINARY
CYD01S36V
CYD02S36V/CYD04S36V
CYD09S36V/CYD18S36V
Document #: 38-06076 Rev. *B
Page 6 of 28
Table 3 summarizes the operation of these registers and the
required input control signals. The MRST control signal is
asynchronous. All the other control signals in Table 3
(CNT/MSK, CNTRST, ADS, CNTEN) are synchronized to the
port’s CLK. All these counter and mask operations are
independent of the port’s chip enable inputs (CE0 and CE1).
Counter enable (CNTEN) inputs are provided to stall the
operation of the address input and utilize the internal address
generated by the internal counter for fast, interleaved memory
applications. A port’s burst counter is loaded when the port’s
address strobe (ADS) and CNTEN signals are LOW. When the
port’s CNTEN is asserted and the ADS is deasserted, the
address counter will increment on each LOW to HIGH
transition of that port’s clock signal. This will Read/Write one
word from/into each successive address location until CNTEN
is deasserted. The counter can address the entire memory
array, and will loop back to the start. Counter reset (CNTRST)
is used to reset the unmasked portion of the burst counter to
0s. A counter-mask register is used to control the counter
wrap.
Counter Reset Operation
All unmasked bits of the counter and mirror registers are reset
to “0.” All masked bits remain unchanged. A Mask Reset
followed by a Counter Reset will reset the counter and mirror
registers to 00000, as will master reset (MRST).
Counter Load Operation
The address counter and mirror registers are both loaded with
the address value presented at the address lines.
Table 3. Address Counter and Counter-Mask Register Control Operation (Any Port) [17, 19]
CLK
MRST CNT/MSK
CNTRST
ADS
CNTEN
Operation
Description
X
L
X
X
X
X
Master Reset
Reset address counter to all 0s and mask
register to all 1s.
H
H
L
X
X
Counter Reset
Reset counter unmasked portion to all 0s.
H
H
H
L
L
Counter Load
Load counter with external address value
presented on address lines.
H
H
H
L
H
Counter Readback Read out counter internal value on address
lines.
H
H
H
H
L
Counter Increment Internally increment address counter value.
H
H
H
H
H
Counter Hold
Constantly hold the address value for
multiple clock cycles.
H
L
L
X
X
Mask Reset
Reset mask register to all 1s.
H
L
H
L
L
Mask Load
Load mask register with value presented on
the address lines.
H
L
H
L
H
Mask Readback
Read out mask register value on address
lines.
H
L
H
H
X
Reserved
Operation undefined
Notes:
18. This section describes the CYD09S36V, CYD04S36V, CYD02S36V, and CYD01S36V which have 18, 17, 16 and 15 address bits.
19. Counter operation and mask register operation is independent of chip enables.