AT INTERFACE DESCRIPTION
Ultra DMA Timing
TIMING PARAMETERS (all times in nanoseconds) | MODE 0 | MODE 1 | MODE 2 | MODE 3 | MODE 4 | ||||||
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| MIN | MAX | MIN | MAX | MIN | MAX | MIN | MAX | MIN | MAX |
tCYC | Cycle Time (from STROBE edge to STROBE edge) | 112 |
| 73 |
| 54 |
| 39 |
| 25 |
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t2CYC | Two cycle time (from rising edge to next rising edge or | 230 |
| 154 |
| 115 |
| 86 |
| 57 |
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| from falling edge to next falling edge of STROBE) |
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tD S | Data setup time (at recipient) | 15 |
| 10 |
| 7 |
| 7 |
| 5 |
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tDH | Data hold time (at recipient) | 5 |
| 5 |
| 5 |
| 5 |
| 5 |
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tDVS | Data valid setup time at sender (time from data bus being | 70 |
| 48 |
| 30 |
| 20 |
| 6 |
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| valid until STROBE edge) |
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tDVH | Data valid hold time at sender (time from STROBE edge | 6 |
| 6 |
| 6 |
| 6 |
| 6 |
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| until data may go invalid) |
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tF S | First STROBE (time for device to send first STROBE) | 0 | 230 | 0 | 200 | 0 | 170 | 0 | 130 | 0 | 120 |
tL I | Limited interlock time (time allowed between an action by | 0 | 150 | 0 | 150 | 0 | 150 | 0 | 100 | 0 | 100 |
| one agent, either host or device, and the following action | ||||||||||
| by the other agent) |
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tMLI | Interlock time with minimum | 20 |
| 20 |
| 20 |
| 20 |
| 20 |
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tU I | Unlimited interlock time | 0 |
| 0 |
| 0 |
| 0 |
| 0 |
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tA Z | Maximum time allowed for outputs to release |
| 10 |
| 10 |
| 10 |
| 10 |
| 10 |
tZAH | Minimum delay time required for output drivers turning on | 20 |
| 20 |
| 20 |
| 20 |
| 20 |
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tZAD | (from released state) | 0 |
| 0 |
| 0 |
| 0 |
| 0 |
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tENV | Envelope time (all control signal transitions are within the | 20 | 70 | 20 | 70 | 20 | 70 | 20 | 55 | 20 | 55 |
| DMACK envelope by this much time) | ||||||||||
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tS R | STROBE to DMARDY (response time to ensure the |
| 50 |
| 30 |
| 20 |
| NA |
| NA |
| synchronous pause case when the recipient is pausing) |
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tRFS |
| 75 |
| 70 |
| 60 |
| 60 |
| 60 | |
| may be sent this long after receiving DMARDY- negation) |
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tR P | 160 |
| 125 |
| 100 |
| 100 |
| 100 |
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| that the sender has paused after negation of |
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tIORDYZ |
| 20 |
| 20 |
| 20 |
| 20 |
| 20 | |
tZ I O R D Y | Minimum time device shall wait before driving IORDY | 0 |
| 0 |
| 0 |
| 0 |
| 0 |
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tACK | Setup and hold times before assertion and negation of | 20 |
| 20 |
| 20 |
| 20 |
| 20 |
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| DMACK- |
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tS S | Time from STROBE edge to STOP assertion when the | 50 |
| 50 |
| 50 |
| 50 |
| 50 |
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| sender is stopping |
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DMARQ |
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(device) |
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tUI |
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DMACK- |
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(host) |
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tA C K | tFS |
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tE N V |
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STOP | tZAD |
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(host) |
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tA C K | tFS |
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tE N V |
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HDMARDY- |
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(host) | tZAD |
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tZIORDY |
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DSTROBE |
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(device) |
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tAZ | tV D S | tDVH |
DD(15:0) |
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tA C K |
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DA0, DA1, DA2, |
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| Figure 5 - 4 |
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Initiating an Ultra DMA Data In Burst
5 – 5