25

COMMERCIALTEMPERATURERANGE

IDT723623/723633/723643 BUS-MATCHING SyncFIFO™

256 x 36, 512 x 36, 1,024 x 36

Figure 17. Timing for Mail1 Register and

NOTE:

1. If Port B is configured for word size, data can be written to the Mail1 Register using A0-A17 (A18-A35 are don't care inputs). In this first case B0-B17 will have valid data (B18-B35 will

be indeterminate). If Port B is configured for byte size, data can be written to the Mail1 Register using A0-A8

(A9-A35 are don't care inputs). In this second case, B0-B8 will have valid data (B9-B35 will be indeterminate).

NOTES:

AF to transition HIGH in the next CLKA cycle. If the time between the rising CLKA edge

AF may transition HIGH one CLKA cycle later than shown.

2. FIFO Write (

CSA = LOW, W/RA = HIGH, MBA = LOW), FIFO read (CSB = LOW, W/RB = HIGH, MBB = LOW). Data in the FIFO output register has been read from the FIFO.

3. D = Maximum FIFO Depth = 256 for the IDT723623, 512 for the IDT723633, 1,024 for the IDT723643.

Figure 16. Timing for

3269 drw18

CLKA

ENA

A0-A35

MBA

CSA

W/

RA

CLKB

MBF1

CSB

MBB

ENB

B0-B35

W/RB

FIFO Output Register

W1 (Remains valid in Mail1 Register after read)

W1

AF

CLKA

ENB

3269 drw17

ENA

CLKB

12

[D-(Y+1)] Words in FIFO

(D-Y) Words in FIFO

(1)