数据搜索系统,热门电子元器件搜索 |
|
SN74V245-EP 数据表(PDF) 11 Page - Texas Instruments |
|
|
SN74V245-EP 数据表(HTML) 11 Page - Texas Instruments |
11 / 42 page SN74V245-EP www.ti.com SCAS932A – DECEMBER 2012 – REVISED JANUARY 2013 WRITE EXPANSION INPUT (WXI) This is a dual-purpose pin. For single-device mode, see Table 6 for additional information. WXI is connected to write expansion out (WXO) of the previous device in the daisy-chain depth-expansion mode. READ EXPANSION INPUT (RXI) This is a dual-purpose pin. For single-device mode, see Table 6 for additional information. RXI is connected to read expansion out (RXO) of the previous device in the daisy-chain depth-expansion mode. OUTPUTS: FULL FLAG/INPUT READY (FF/IR) This is a dual-purpose pin. In FWFT mode, the input ready (IR) function is selected. IR goes low when memory space is available for writing data. When there is no free space left, IR goes high, inhibiting further write operations. In standard mode, the FF function is selected. When the FIFO is full, FF goes low, inhibiting further write operations. When FF is high, the FIFO is not full. If no reads are performed after a reset, FF goes low after D writes to the FIFO. D = 4096. IR goes high after D writes to the FIFO. D = 4097. The additional word in FWFT mode is due to the capacity of the memory plus output register. FF/IR is synchronous and updated on the rising edge of WCLK. EMPTY FLAG/OUTPUT READY (EF/OR) This is a dual-purpose pin. In FWFT mode, the OR function is selected. OR goes low at the same time the first word written to an empty FIFO appears valid on the outputs. OR stays low after the RCLK low-to-high transition that shifts the last word from the FIFO memory to the outputs. OR goes high only with a true read (RCLK with REN low). The previous data stays at the outputs, indicating that the last word was read. Further data reads are inhibited until OR goes low again. In the standard mode, the EF function is selected. When the FIFO is empty, EF goes low, inhibiting further read operations. When EF is high, the FIFO is not empty. EF/OR is synchronous and updated on the rising edge of RCLK. PROGRAMMABLE ALMOST-FULL FLAG (PAF) PAF goes low when the FIFO reaches the almost-full condition. In FWFT mode, if no reads are performed, PAF goes low after 4097 - m. Default values for m are in Table 4 and Table 5. In standard mode, if no reads are performed after reset (RS), PAF goes low after 4096 – m writes. The offset m is defined in Table 3. If asynchronous PAF configuration is selected, PAF is asserted low on the low-to-high transition of WCLK. PAF is reset to high on the low-to-high transition of RCLK. If synchronous PAF configuration is selected (see Table 6), PAF is updated on the rising edge of WCLK. PROGRAMMABLE ALMOST-EMPTY FLAG (PAE) PAE goes low when the FIFO reaches the almost-empty condition. In FWFT mode, PAE goes low when there are n + 1 words, or fewer, in the FIFO. In standard mode, PAE goes low when there are n words or fewer in the FIFO. The offset n is defined as the empty offset. The default values for n are noted in Table 4 and Table 5. If there is no empty offset specified, PAE is low when the device is 127 away from completely empty. If asynchronous PAE configuration is selected, 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). If synchronous PAE configuration is selected (see Table 6), PAE is updated on the rising edge of RCLK. Copyright © 2012–2013, Texas Instruments Incorporated Submit Documentation Feedback 11 Product Folder Links: SN74V245-EP |
类似零件编号 - SN74V245-EP |
|
类似说明 - SN74V245-EP |
|
|
链接网址 |
隐私政策 |
ALLDATASHEETCN.COM |
ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 链接交换 | 制造商名单 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 |