CY7C0430BV
CY7C0430CV
Document #: 38-06027 Rev. *B Page 24 of 37
Address Counter Control Operations
Counter enable inputs are provided to stall the operation of the
address input and utilize the internal address generated by the
internal counter for the fast interleaved memory applications.
A port’s burst counter is loaded with the port’s Counter Load
pin (CNTLD). When the port’s Counter Increment (CNTINC) is
asserted, 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
CNTINC is deasserted. Depending on the mask register state,
the counter can address the entire memory array and will loop
back to start. Counter Reset (CNTRST) is used to reset the
Burst Counter (the Mask Register value is unaffected). When
using the counter in readback mode, the internal address
value of the counter will be read back on the address lines
when Counter Readback Signal (CNTRD) is asserted.
Figure1 provides a blo ck diagram of the readback operation.
Table 2 lists control signals required for counter operations.
The signals are listed based on their priority. For example,
Master Reset takes precedence over Counter Reset, and
Counter Load has lower priority than Mask Register Load
(described below). All counter operations are independent of
Chip Enables (CE0 and CE1). When the address readback
operation is performed the data I/Os are three-stated (if CEs
are active) and one-clock cycle (no-operation cycle) latency is
experienced. The address will be read at time tCA2 from the
rising edge of the clock following the no-operation cycle. The
read back address can be either of the burst counter or the
mask register based on the levels of Counter Read signal
(CNTRD) and Mask Register Read signal (MKRD). Both
signals are synchronized to the port's clock as shown in
Table 2 . Counter read has a higher priority than mask read.
Addr.
Readback

Counter/

Address

Register

CLK
CNTLD = 1
CNTINC = 1
CNTRST = 1
MKLD = 1
MKRD
CNTRD
Memory
Array
Mask
Register
Readback
Register
Bidirectional
Address Lines
Figure 1. Counter and Mask Register Read Back on Address Lines
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