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| | {{ARM Embedded Tutorial - Raspberry Pi Pico running at full CPU speed}} | | {{ARM Embedded Tutorial - Raspberry Pi Pico running at full CPU speed}} |
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| − | In the simple Blinky example we did the bare minimum that is necessary to blink a LED.
| + | This tutorial is not needed anymore, now Pico is enabled to run at full speed in Initialization Code. |
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| − | Now we increase CPU speed to full power with the help of the init_clock procedure from <tt>clocks.c.obj</tt>.
| + | [[ARM Embedded Tutorial - FPC and the Raspberry Pi Pico|Back to main Pico Page]] |
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| − | First step we need to do is to add the <tt>clocks.c.obj</tt> file to our code. When we do that and compile the code we are left again with linking errors because <tt>clocks.c.obj</tt> has dependencies on other code parts.
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| − | After fiddling arround a bit we end up with the needed list of dependencies to link in:
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| − | <syntaxhighlight lang=pascal>
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| − | program Blinky;
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| − | {$L platform.c.obj}
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| − | {$L gpio.c.obj}
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| − | {$L clocks.c.obj}
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| − | {$L xosc.c.obj}
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| − | {$L pll.c.obj}
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| − | {$L platform.c.obj}
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| − | {$L watchdog.c.obj}
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| − | </syntaxhighlight>
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| − | Now we add clocks_init to our code and we are also now able to initialize all peripherals:
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| − | <syntaxhighlight lang=pascal>
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| − | procedure runtime_init;
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| − | const
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| − | RESETS_SAFE_BITS= %1111111111100110110111111;
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| − | RESETS_PRECLOCK_BITS= %0001111000100110110111110;
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| − | RESETS_POSTCLOCK_BITS=%1110000111000000000000001;
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| − | begin
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| − | resets.reset_set := RESETS_SAFE_BITS;
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| − | resets.reset_clr := RESETS_PRECLOCK_BITS;
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| − | repeat
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| − | until (resets.reset_done and RESETS_PRECLOCK_BITS) = RESETS_PRECLOCK_BITS;
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| − | clocks_init;
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| − | resets.reset_clr := RESETS_POSTCLOCK_BITS;
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| − | repeat
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| − | until (resets.reset_done and RESETS_POSTCLOCK_BITS) = RESETS_POSTCLOCK_BITS;
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| − | end;
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| − | </syntaxhighlight>
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| − | We start the compiler again and there is still one dependency missing, so we add a bit of code to get this fixed:
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| − | <syntaxhighlight lang=pascal>
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| − | function __aeabi_uidiv(const numerator : uint32; denominator : uint32):uint32; public name '__aeabi_uidiv';
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| − | begin
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| − | Result := numerator div denominator;
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| − | end;
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| − | </syntaxhighlight>
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| − | This dependency comes with the gcc compiler but we are lazy and use this simple (likely slower) alternative.
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| − | After this final step we are able to blink the LED's at full CPU speed, so we increase our delay loop because we are now faster with waiting:
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| − | <syntaxhighlight lang=pascal>
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| − | program Blinky;
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| − | | |
| − | {$L platform.c.obj}
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| − | {$L gpio.c.obj}
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| − | {$L clocks.c.obj}
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| − | {$L xosc.c.obj}
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| − | {$L pll.c.obj}
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| − | {$L watchdog.c.obj}
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| − | | |
| − | procedure clocks_init; external;
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| − | procedure gpio_init(gpio : longWord); external;
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| − | | |
| − | function __aeabi_uidiv(const numerator : uint32; denominator : uint32):uint32; public name '__aeabi_uidiv';
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| − | begin
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| − | Result := numerator div denominator;
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| − | end;
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| − | | |
| − | procedure runtime_init;
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| − | const
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| − | RESETS_SAFE_BITS= %1111111111100110110111111;
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| − | RESETS_PRECLOCK_BITS= %0001111000100110110111110;
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| − | RESETS_POSTCLOCK_BITS=%1110000111000000000000001;
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| − | begin
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| − | resets.reset_set := RESETS_SAFE_BITS;
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| − | resets.reset_clr := RESETS_PRECLOCK_BITS;
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| − | repeat
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| − | until (resets.reset_done and RESETS_PRECLOCK_BITS) = RESETS_PRECLOCK_BITS;
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| − | clocks_init;
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| − | resets.reset_clr := RESETS_POSTCLOCK_BITS;
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| − | repeat
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| − | until (resets.reset_done and RESETS_POSTCLOCK_BITS) = RESETS_POSTCLOCK_BITS;
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| − | end;
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| − | | |
| − | procedure gpio_set_dir(gpio : longWord; &out : longbool);
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| − | var
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| − | mask : longWord;
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| − | begin
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| − | mask := 1 shl gpio;
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| − | if out = true then
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| − | sio.gpio_oe_set := mask
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| − | else
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| − | sio.gpio_oe_clr := mask;
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| − | end;
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| − | | |
| − | procedure gpio_put(gpio : longWord; value : boolean);
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| − | var
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| − | mask : longWord;
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| − | begin
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| − | mask := 1 shl gpio;
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| − | if value=true then
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| − | sio.gpio_set := mask
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| − | else
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| − | sio.gpio_clr := mask;
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| − | end;
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| − | | |
| − | const
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| − | LED_PIN=25;
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| − | GPIO_OUT=true;
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| − | var
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| − | i : longWord;
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| − | begin
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| − | runtime_init;
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| − | gpio_init(LED_PIN);
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| − | gpio_set_dir(LED_PIN,GPIO_OUT);
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| − | repeat
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| − | gpio_put(LED_PIN,true);
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| − | for i := 0 to 3000000 do ;
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| − | gpio_put(LED_PIN,false);
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| − | for i := 0 to 3000000 do ;
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| − | until 1=0;
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| − | end.
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| − | </syntaxhighlight>
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