 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
Z80 Datasheet(PDF) 178 Page - Zilog, Inc. |
|
|
|||||||||||||||||||||||||||||
Z80 Datasheet(HTML) 178 Page - Zilog, Inc. |
|
|
178 / 330 page  <%27 2GTKRJGTCNU 7UGT /CPWCN UM008101-0601 Direct Memory Access Figure 65. Bus Request and Acceptance Timing Continuous mode is the only instance when a pulse on RDY allows the DMA to become bus master.In this event, the DMA becomes bus master but does not begin operations. When the DMA detects a Low on BAI for two consecutive rising edges of CLK, the DMA begins transferring data on the next rising edge of CLK. In Byte mode, after each byte is transferred, the DMA waits until its BAI line goes inactive before requesting the bus again on BUSREQ for the next byte transfer. This feature allows a minimum of one CPU machine cycle to occur between each byte transferred. Bus Release Byte-at-a-Time In Byte mode, BUSREQ is brought High on the rising edge of CLK prior to the end of each read cycle (search-only) or write cycle (transfer and trans- fer/search) as illustrated in Figure 66. This action occurs regardless of the state of RDY. There is no possibility of confusion when a Z80 CPU is used because the CPU cannot begin an operation until the following clock cycle. Nor does this condition affect most other CPUs. The result of timing is one- clock-cycle less time needed for a byte transfer. BUSREQ RDY Active Inactive DMA Inactive DMA Active BAI CLK Note: RDY is detected as a level, not an edge |
|
Link URL |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link to Datasheet | 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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
