SPRS292 − OCTOBER 2005
GENERAL-PURPOSE INPUT/OUTPUT (GPIO) PORT TIMING
timing requirements for GPIO inputs†‡ | (see Figure 53) |
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| GDPA−167 |
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| ZDPA−167 |
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NO. |
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| −200 |
| UNIT |
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| −250 |
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| MIN | MAX |
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1 | tw(GPIH) | Pulse duration, GPIx high |
| 4P |
| ns |
2 | tw(GPIL) | Pulse duration, GPIx low |
| 4P |
| ns |
†P = 1/CPU clock frequency in ns. For example, when running parts at 250 MHz, use P = 4 ns.
‡The pulse width given is sufficient to generate a CPU interrupt or an EDMA event. However, if a user wants to have the DSP recognize the GPIx changes through software polling of the GPIO register, the GPIx duration must be extended to at least 24P to allow the DSP enough time to access the GPIO register through the CFGBUS.
switching characteristics over recommended operating conditions for GPIO outputs†§ (see Figure 53)
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| GDPA−167 |
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| ZDPA−167 |
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NO. |
| PARAMETER | −200 |
| UNIT |
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| −250 |
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| MIN | MAX |
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3 | tw(GPOH) | Pulse duration, GPOx high | 12P − 3 |
| ns |
4 | tw(GPOL) | Pulse duration, GPOx low | 12P − 3 |
| ns |
†P = 1/CPU clock frequency in ns. For example, when running parts at 250 MHz, use P = 4 ns.
§The number of CFGBUS cycles between two
GPIx
GPOx
2 1
4
3
Figure 53. GPIO Port Timing
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