PRELIMINARY
CYD01S36V
CYD02S36V/CYD04S36V
CYD09S36V/CYD18S36V
Document #: 38-06076 Rev. *B
Page 5 of 28
Master Reset
The FLEx36 family devices undergo a complete reset by
taking its MRST input LOW. The MRST input can switch
asynchronously to the clocks. An MRST initializes the internal
burst counters to zero, and the counter mask registers to all
ones (completely unmasked). MRST also forces the Mailbox
Interrupt (INT) flags and the Counter Interrupt (CNTINT) flags
HIGH. MRST must be performed on the FLEx36 family
devices after power-up.
Mailbox Interrupts
The upper two memory locations may be used for message
passing and permit communications between ports. Table 2
shows the interrupt operation for both ports of CYD18S36V.
The highest memory location, 7FFFF is the mailbox for the
right port and 7FFFE is the mailbox for the left port. Table 2
shows that in order to set the INTR flag, a Write operation by
the left port to address 7FFFF will assert INTR LOW. At least
one byte has to be active for a Write to generate an interrupt.
A valid Read of the 7FFFF location by the right port will reset
INTR HIGH. At least one byte has to be active in order for a
Read to reset the interrupt. When one port Writes to the other
port’s mailbox, the INT of the port that the mailbox belongs to
is asserted LOW. The INT is reset when the owner (port) of the
mailbox Reads the contents of the mailbox. The interrupt flag
is set in a flow-thru mode (i.e., it follows the clock edge of the
writing port). Also, the flag is reset in a flow-thru mode (i.e., it
follows the clock edge of the reading port).
Each port can read the other port’s mailbox without resetting
the interrupt. And each port can write to its own mailbox
without setting the interrupt. If an application does not require
message passing, INT pins should be left open.
Address Counter and Mask Register
Operations[18]
This section describes the features only apply to 1Mbit, 2 Mbit,
4 Mbit and 9 Mbit devices. It does not apply to 18Mbit device.
Each port of these devices has a programmable burst address
counter. The burst counter contains three registers: a counter
register, a mask register, and a mirror register.
The counter register contains the address used to access the
RAM array. It is changed only by the Counter Load, Increment,
Counter Reset, and by master reset (MRST) operations.
The mask register value affects the Increment and Counter
Reset operations by preventing the corresponding bits of the
counter register from changing. It also affects the counter
interrupt output (CNTINT). The mask register is changed only
by the Mask Load and Mask Reset operations, and by the
MRST. The mask register defines the counting range of the
counter register. It divides the counter register into two
regions: zero or more “0s” in the most significant bits define
the masked region, one or more “1s” in the least significant bits
define the unmasked region. Bit 0 may also be “0,” masking
the least significant counter bit and causing the counter to
increment by two instead of one.
The mirror register is used to reload the counter register on
increment operations (see “retransmit,” below). It always
contains the value last loaded into the counter register, and is
changed only by the Counter Load, and Counter Reset opera-
tions, and by the MRST.
Notes:
13. CE is internal signal. CE = LOW if CE0 = LOW and CE1 = HIGH. For a single Read operation, CE only needs to be asserted once at the rising edge of the CLK
and can be deasserted after that. Data will be out after the following CLK edge and will be three-stated after the next CLK edge.
14. OE is “Don’t Care” for mailbox operation.
15. At least one of BE0, BE1, BE2, or BE3 must be LOW.
16. A17x is a NC for CYD04S36V, therefore the Interrupt Addresses are 1FFFF and 1FFFE. A17x and A16x are NC for CYD02S36V, therefore the Interrupt Addresses
are FFFF and FFFE; A17x, A16x and A15x are NC for CYD01S36V, therefore the Interrupt Addresses are 7FFF and 7FFE.
17. “X” = “Don’t Care,” “H” = HIGH, “L” = LOW.
TCK
JTAG Test Clock Input.
TDO
JTAG Test Data Output. TDO transitions occur on the falling edge of TCK. TDO
is normally three-stated except when captured data is shifted out of the JTAG TAP.
VSS
Ground Inputs.
VCORE
Core Power Supply.
VTTL
LVTTL Power Supply for JTAG IOs
Pin Definitions (continued)
Left Port
Right Port
Description
Table 2. Interrupt Operation Example [1, 13, 14, 15, 16, 17]
Function
Left Port
Right Port
R/WL
CEL
A0L–18L
INTL
R/WR
CER
A0R–18R
INTR
Set Right INTR Flag
L
L
7FFFF
X
X
X
X
L
Reset Right INTR Flag
X
XXX
H
L
7FFFF
H
Set Left INTL Flag
X
X
X
L
L
L
7FFFE
X
Reset Left INTL Flag
H
L
7FFFE
H
X
X
X
X
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