I want to replace an old pc which were used for controlling some devices in our lab. For this purpose we need a small pc with at least 26 GPIO-ports and the ability to send the retrieved data over network. The old pc was a 486er with DOS 6.2. So, is the raspberry fast enough for replacing this pc, (there should be enough GPIO-Pins according to the datasheet), or should I look for something else like a beaglebone black?

The target of the mini pc is to control some stepper motors (which have already a driver) over GPIO-Pins, but we maybe we want to extend this, so I am not sure if 26 GPIO-Ports are enough. Frequency of shifting is not known at the moment, earlier the switching was done by an isa card.

  • The B+ has 26 possible pins if you use all pins as GPIO i.e. exclude serial etc. This can easily be expanded with add-ons. The processing power is roughly equivalent to 486. – Milliways Sep 15 '14 at 13:06
  • To improve the answer, could you tell more about your application, e.g. what are the requirement for the GPIO lines (what do they do, what's the frequency of switching, etc.?), how likely is it that the number of needed GPIO pins is going up in the near future? – Ghanima Sep 16 '14 at 8:47

Computational power should be sufficient to replace a 486er PC. At the RPi Type B+ a total of 26 GPIO pins are available at the pin header J8 (see schematics) plus two lines reserved for special functions of an I2C interface for an EEPROM.

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    So, I should rather use an beaglebone black or something like this? – arc_lupus Sep 15 '14 at 13:11
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    gpios 2-27 (so 26 in total) are available on the B+ expansion header. Alternatively you could use the I2C or SPI buses to add another 128 gpios using such chips as the MCP23017/MCP23S17. – joan Sep 15 '14 at 13:17
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    I think a beaglebone black will probably suit your needs better. More GPIO and the PRUs may be useful depending on your application. – Craig Sep 15 '14 at 17:47
  • You are right. Without knowing the specifications of the application however we cannot know whether fast GPIO and PRU are needed or whether simple port expansion will do the trick. If the price is not an issue I'd also go for the BBB. – Ghanima Sep 16 '14 at 8:49

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