Electronic Components Datasheet Search |
|
IDT72235LB25PFI Datasheet(PDF) 7 Page - Integrated Device Technology |
|
IDT72235LB25PFI Datasheet(HTML) 7 Page - Integrated Device Technology |
7 / 16 page 7 IDT72205LB/72215LB/72225LB/72235LB/72245LB CMOS SyncFIFO™ 256 x 18-BIT, 512 x 18, 1,024 x 18, 2,048 x 18 and 4,096 x 18 Commercial And Industrial Temperature Ranges When the LDpin is LOW and WEN is HIGH, the WCLK input is disabled; then a signal at this input can neither increment the write offset register pointer, nor execute a write. The contents of the offset registers can be read on the output lines when the LD pin is set LOW and REN is set LOW; then, data can be read on the LOW-to-HIGH transition of the read clock (RCLK). The act of reading the control registers employs a dedicated read offset register pointer. (The read and write pointers operate independently). A read and a write should not be performed simultaneously to the offset registers. FIRST LOAD ( FL FL FL FL FL) FL is grounded to indicate operation in the Single Device or Width Expansion mode. In the Depth Expansion configuration, FL is grounded to indicate it is the first device loaded and is set to HIGH for all other devices in the Daisy Chain. (See Operating Configurations for further details.) WRITE EXPANSION INPUT ( WXI WXI WXI WXI WXI) This is a dual purpose pin. WXI is grounded to indicate operation in the Single Device or Width Expansion mode. WXI is connected to Write Expansion Out ( WXO) of the previous device in the Daisy Chain Depth Expansion mode. READ EXPANSION INPUT ( RXI RXI RXI RXI RXI) This is a dual purpose pin. RXI is grounded to indicate operation in the Single Device or Width Expansion mode. RXI is connected to Read Expansion Out ( RXO) of the previous device in the Daisy Chain Depth Expansion mode. OUTPUTS: FULL FLAG ( FF FF FF FF FF) When the FIFO is full, FF will go LOW, inhibiting further write operations. When FF is HIGH, the FIFO is not full. If no reads are performed after a reset, FF will go LOW after D writes to the FIFO. D = 256 writes for the IDT72205LB, 512 for the IDT72215LB, 1,024 for the IDT72225LB, 2,048 for the IDT72235LB and 4,096 for the IDT72245LB. The FF is updated on the LOW-to-HIGH transition of the write clock (WCLK). Number of Words in FIFO Memory 72205 72215 72225 72235 72245 FF FF FF FF FF PAF PAF PAF PAF PAF HF HF HF HF HF PAE PAE PAE PAE PAE EF EF EF EF EF 00 0 0 0 H H H L L 1 to n(1) 1 to n(1) 1 to n(1) 1 to n(1) 1 to n(1) HH H L H (n + 1) to 128 (n + 1) to 256 (n + 1) to 512 (n + 1) to 1,024 (n + 1) to 2,048 H H H H H 129 to (256-(m+1)) 257 to (512-(m+1)) 513 to (1,024-(m+1)) 1,025 to (2,048-(m+1)) 2,049 to (4,096-(m+1)) H H L H H (256-m)(2) to 255 (512-m)(2) to 511 (1,024-m)(2) to 1,023 (2,048-m)(2) to 2,047 (4,096-m)(2) to 4,095 H L L H H 256 512 1,024 2,048 4,096 L L L H H NOTES: 2766 tbl 09 1. n = Empty Offset (Default Values : IDT72205 n=31, IDT72215 n = 63, IDT72225/72235/72245 n = 127) 2. m = Full Offset (Default Values : IDT72205 n=31, IDT72215 n = 63, IDT72225/72235/72245 n = 127) TABLE I — STATUS FLAGS EMPTY FLAG ( EF EF EF EF EF) When the FIFO is empty, EF will go LOW, inhibiting further read operations. When EF is HIGH, the FIFO is not empty. The EF is updated on the LOW-to-HIGH transition of the read clock (RCLK). PROGRAMMABLE ALMOST-FULL FLAG ( PAF PAF PAF PAF PAF) The Programmable Almost-Full Flag ( PAF) will go LOW when FIFO reaches the Almost-Full condition. If no reads are performed after Reset ( RS), the PAF will go LOW after (256-m) writes for the IDT72205LB, (512-m) writes for the IDT72215LB, (1,024-m) writes for the IDT72225LB, (2,048–m) writes for the IDT72235LB and (4,096–m) writes for the IDT72245LB. The offset “m” is defined in the FULL offset register. If there is no Full offset specified, the PAF will be LOW when the device is 31 away from completely full for IDT72205LB, 63 away from completely full for IDT72215LB, and 127 away from completely full for IDT72225LB/72235LB/72245LB. The PAF is asserted LOW on the LOW-to-HIGH transition of the write clock (WCLK). PAF is reset to HIGH on the LOW- to-HIGH transition of the read clock (RCLK). Thus PAF is asynchronous. PROGRAMMABLE ALMOST-EMPTY FLAG ( PAE PAE PAE PAE PAE) The Programmable Almost-Empty Flag ( PAE) will go LOW when the read pointer is “n+1” locations less than the write pointer. The offset “n” is defined in the EMPTY offset register. If there is no Empty offset specified, the Programmable Almost-Empty Flag ( PAE) will be LOW when the device is 31 away from completely empty for IDT72205LB, 63 away from completely empty for IDT72215LB, and 127 away from com- pletely empty for IDT72225LB/72235LB/72245LB. The PAE is asserted LOW on the LOW-to-HIGH transition of the read clock (RCLK). PAE is reset to HIGH on the LOW- to-HIGH transition of the write clock (WCLK). Thus PAE is asynchronous. WRITE EXPANSION OUT/HALF-FULL FLAG ( WXO WXO WXO WXO WXO/HF HF HF HF HF) This is a dual-purpose output. In the Single Device and Width Expansion mode, when Write Expansion In ( WXI) and Read Expansion In ( RXI) are grounded, this output acts as an indication of a half-full memory. |
Similar Part No. - IDT72235LB25PFI |
|
Similar Description - IDT72235LB25PFI |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |