Dedicated DSP for delayed replay I'm looking for a dedicated DSP chip that will allow sampling and delayed replay of a signal, given the following parameters:


buffer should be integrated
configuration of the DSP chip (if needed) should be possible via host CPU (SPI or serial)
starting and stopping the sampling/replay should be possible via a dedicated pin
reading the samples via the host CPU is NOT required!
sampling should be done with a frequency of at least 2MHz (since a temporal resolution of 1 µs is required)
since this is for replaying a digital signal, a low resolution (even 1 bit per sample) is possible
buffering should allow for 250 ms period


I did not find any stand-alone DSP with this characteristics.
Hard to believe, that you actually looked. You probably don't even need a DSP for that, a normal microcontroller should be sufficient.

For example, the STM32F4-Discovery board comes with an ARM Cortex-M3 that has several ADC channels that can do 2.4MSps each and up to 7.2MSps in interleaved mode. There's a DAC for signal output as well. But since your signal is digital anyways, you can probably sample with just a normal digital input pin. If 1bit per sample is enough, 250ms of a 2MHz sampled signal require 62500bytes which fits into the memory of the ARM quite well.