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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Cortex GNAT RTS: BBC micro:bit tick rate
Date: Tue, 24 Jul 2018 12:44:18 +0100
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Date: 2018-07-24T12:44:18+01:00
List-Id: <comp.lang.ada>

As announced recently, Cortex GNAT RTS now supports the BBC micro:bit.

Because the nRF51822 MCU doesn't support SysTick, it has to be simulated
using the RTC peripheral, which runs at 32,768 Hz.

At first I thought it wouldn't generate interrupts faster than 100 Hz
anyway, but this turns out to be because I was disabling/enabling
interrupts every time. It will go much faster than that (I don't know
how much time is left for the CPU to do anything else, though).

So, the question: is there any problem with having Ada.Real_Time.Tick be
1/1024 second? (with GNAT, it's usually/always a decimal fraction).