Raspberry Pi : BerryClip: what changed

Revision 1 to 2. Removed lines have a minus sign; added lines have a plus sign.

Old	New		Line
1	1		# Raspberry Pi : BerryClip
2	2
3	3		![](/wiki-images/3/3f/Pi_berryclip.png)
4	4
5	5		The BerryClip 6 LED Board is a add-on board for the Raspberry Pi. It consists of a PCB populated with 6 coloured LEDs, one switch and one buzzer. It is easy to attach to the Pi’s GPIO header.
6	6
7	7		## Hardware
8	8
9	9		![](/wiki-images/b/bd/Pi_berryclip_sch.png)
10	10
11	11		The following list shows the mapping between the components, the header pins and the GPIO references :
12	12
13	13		- LED 1 - Pin 7 - GPIO4
14	14		- LED 2 - Pin 11 - GPIO17
15	15		- LED 3 - Pin 15 - GPIO22
16	16		- LED 4 - Pin 19 - GPIO10
17	17		- LED 5 - Pin 21 - GPIO9
18	18		- LED 6 - Pin 23 - GPIO11
19	19		- Buzzer - Pin 24 - GPIO8
20	20		- Switch - Pin 26 - GPIO7
21	21
22	22		\| GPIO \| Pin \| \| Pin \| GPIO \|
23	23		\|--------\|-----\|-----\|-----\|--------\|
24	24		\| GPIO7 \| 26 \| \| 25 \| GND \|
25	25		\| GPIO8 \| 24 \| \| 23 \| GPIO11 \|
26	26		\| GPIO25 \| 22 \| \| 21 \| GPIO9 \|
27	27		\| GND \| 20 \| \| 19 \| GPIO10 \|
28	28		\| GPIO24 \| 18 \| \| 17 \| +3.3V \|
29	29		\| GPIO23 \| 16 \| \| 15 \| GPIO22 \|
30	30		\| GND \| 14 \| \| 13 \| GPIO27 \|
31	31		\| GPIO18 \| 12 \| \| 11 \| GPIO17 \|
32	32		\| GPIO15 \| 10 \| \| 9 \| GND \|
33	33		\| GPIO14 \| 8 \| \| 7 \| GPIO4 \|
34	34		\| GND \| 6 \| \| 5 \| GPIO3 \|
35	35		\| +5V \| 4 \| \| 3 \| GPIO2 \|
36	36		\| +5V \| 2 \| \| 1 \| +3.3V \|
37	37
38	38		## Software
39	39
40	40		![](/wiki-images/c/c5/Pi_berryclip_uml.png)
41	41
42	42		The following example lists a program that controls berryClip.
43	43
44	44		The code requires to be run as root (eg. sudo ./berryclipdemo).
45	45
46	46		\| Level \| \| Unit \|
47	47		\|----\|----\|----\|
48	48		\| 1 \| User interface, Application level \| unit1.pas, unit1.lfm, berryclipdemo.lpr \|
49	49		\| 2 \| Board level \| uberryclip.pas \|
50	50		\| 3 \| \| uraspberrypi.pas \|
51	51		\| 4 \| I/O driver \| pi_io_unit.pas \|
52	52
53	53		### User interface
54	54
55	55		![](/wiki-images/e/e5/Pi_berryclipdemo.png)
56	56
57	57		The user interface consists of the buttons that control the LEDs and buzzer. In addition, the switch status is displayed on LED. LEDs state on the circuit board is displayed with the LEDs on the form. The berryclipdemo program uses the following components: [[TApplicationProperties]], [[TButton]], [[TShape]] and [[TToggleBox]].
58	58
59	59		#### unit1.pas
60	60
61	61		``` pascal
62	62		unit Unit1;
63	63
64	64		{$mode objfpc}{$H+}
65	65
66	66		interface
67	67
68	68		uses
69	69		Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
70	70		ExtCtrls, uberryclip;
71	71
72	72		type
73	73
74	74		{ TForm1 }
75	75
76	76		TForm1 = class(TForm)
77	77		ApplicationProperties1: TApplicationProperties;
78	78		Button1: TButton;
79	79		Led4ToggleBox: TToggleBox;
80	80		Led6ToggleBox: TToggleBox;
81	81		Led2ToggleBox: TToggleBox;
82	82		Led3ToggleBox: TToggleBox;
83	83		Led1ToggleBox: TToggleBox;
84	84		Led5ToggleBox: TToggleBox;
85	85		Shape1: TShape;
86	86		Shape2: TShape;
87	87		Shape3: TShape;
88	88		Shape4: TShape;
89	89		Shape5: TShape;
90	90		Shape6: TShape;
91	91		Shape7: TShape;
92	92		procedure ApplicationProperties1Idle(Sender: TObject; var Done: Boolean);
93	93		procedure Button1MouseDown(Sender: TObject; Button: TMouseButton;
94	94		Shift: TShiftState; X, Y: Integer);
95	95		procedure Button1MouseUp(Sender: TObject; Button: TMouseButton;
96	96		Shift: TShiftState; X, Y: Integer);
97	97		procedure FormCreate(Sender: TObject);
98	98		procedure FormDestroy(Sender: TObject);
99	99		procedure Led1ToggleBoxChange(Sender: TObject);
100	100		procedure Led2ToggleBoxChange(Sender: TObject);
101	101		procedure Led3ToggleBoxChange(Sender: TObject);
102	102		procedure Led4ToggleBoxChange(Sender: TObject);
103	103		procedure Led5ToggleBoxChange(Sender: TObject);
104	104		procedure Led6ToggleBoxChange(Sender: TObject);
105	105		private
106	106		{ private declarations }
107	107		Berry_Clip:TBerryClip;
108	108		public
109	109		{ public declarations }
110	110		end;
111	111
112	112		var
113	113		Form1: TForm1;
114	114
115	115		implementation
116	116
117	117		{$R *.lfm}
118	118
119	119		{ TForm1 }
120	120
121	121		procedure TForm1.ApplicationProperties1Idle(Sender: TObject; var Done: Boolean);
122	122		begin
123	123		if Berry_Clip.ReadSwitch
124	124		then shape7.Brush.Color:=clBlack
125	125		else shape7.Brush.Color:=clWhite;
126	126		end;
127	127
128	128		procedure TForm1.Button1MouseDown(Sender: TObject; Button: TMouseButton;
129	129		Shift: TShiftState; X, Y: Integer);
130	130		begin
131	131		Berry_Clip.SetBuzzerOn;
132	132		end;
133	133
134	134		procedure TForm1.Button1MouseUp(Sender: TObject; Button: TMouseButton;
135	135		Shift: TShiftState; X, Y: Integer);
136	136		begin
137	137		Berry_Clip.SetBuzzerOff;
138	138		end;
139	139
140	140		procedure TForm1.FormCreate(Sender: TObject);
141	141		begin
142	142		Berry_Clip := TBerryClip.Create;
143	143		end;
144	144
145	145		procedure TForm1.FormDestroy(Sender: TObject);
146	146		begin
147	147		Berry_Clip.Free;
148	148		end;
149	149
150	150		procedure TForm1.Led1ToggleBoxChange(Sender: TObject);
151	151		begin
152	152		if Led1ToggleBox.Checked then
153	153		begin
154	154		Berry_Clip.SetLedOn(1);
155	155		shape1.Brush.Color:=clRed ;
156	156		end
157	157		else
158	158		begin
159	159		Berry_Clip.SetLedOff(1);
160	160		shape1.Brush.Color:=clWhite;
161	161		end;
162	162		end;
163	163
164	164		procedure TForm1.Led2ToggleBoxChange(Sender: TObject);
165	165		begin
166	166		if Led2ToggleBox.Checked then
167	167		begin
168	168		Berry_Clip.SetLedOn(2);
169	169		shape2.Brush.Color:=clRed;
170	170		end
171	171		else
172	172		begin
173	173		Berry_Clip.SetLedOff(2);
174	174		shape2.Brush.Color:=clWhite;
175	175		end;
176	176		end;
177	177
178	178		procedure TForm1.Led3ToggleBoxChange(Sender: TObject);
179	179		begin
180	180		if Led3ToggleBox.Checked then
181	181		begin
182	182		Berry_Clip.SetLedOn(3);
183	183		shape3.Brush.Color:=clYellow;
184	184		end
185	185		else
186	186		begin
187	187		Berry_Clip.SetLedOff(3);
188	188		shape3.Brush.Color:=clWhite;
189	189		end;
190	190		end;
191	191
192	192		procedure TForm1.Led4ToggleBoxChange(Sender: TObject);
193	193		begin
194	194		if Led4ToggleBox.Checked then
195	195		begin
196	196		Berry_Clip.SetLedOn(4);
197	197		shape4.Brush.Color:=clYellow;
198	198		end
199	199		else
200	200		begin
201	201		Berry_Clip.SetLedOff(4);
202	202		shape4.Brush.Color:=clWhite;
203	203		end;
204	204		end;
205	205
206	206		procedure TForm1.Led5ToggleBoxChange(Sender: TObject);
207	207		begin
208	208		if Led5ToggleBox.Checked then
209	209		begin
210	210		Berry_Clip.SetLedOn(5);
211	211		shape5.Brush.Color:=clGreen;
212	212		end
213	213		else
214	214		begin
215	215		Berry_Clip.SetLedOff(5);
216	216		shape5.Brush.Color:=clWhite;
217	217		end;
218	218		end;
219	219
220	220		procedure TForm1.Led6ToggleBoxChange(Sender: TObject);
221	221		begin
222	222		if Led6ToggleBox.Checked then
223	223		begin
224	224		Berry_Clip.SetLedOn(6);
225	225		shape6.Brush.Color:=clGreen;
226	226		end
227	227		else
228	228		begin
229	229		Berry_Clip.SetLedOff(6);
230	230		shape6.Brush.Color:=clWhite;
231	231		end;
232	232		end;
233	233
234	234		end.
235	235		```
236	236
237	237		#### unit1.lfm
238	238
239		-	~~``` pascal~~
	239	+	``` lfm
240	240		object Form1: TForm1
241	241		Left = 269
242	242		Height = 184
243	243		Top = 175
244	244		Width = 176
245	245		Caption = 'BerryClip'
246	246		ClientHeight = 184
247	247		ClientWidth = 176
248	248		OnCreate = FormCreate
249	249		OnDestroy = FormDestroy
250	250		object Led2ToggleBox: TToggleBox
251	251		Left = 8
252	252		Height = 24
253	253		Top = 32
254	254		Width = 128
255	255		Caption = 'Led2ToggleBox'
256	256		OnChange = Led2ToggleBoxChange
257	257		TabOrder = 0
258	258		end
259	259		object Led1ToggleBox: TToggleBox
260	260		Left = 8
261	261		Height = 24
262	262		Top = 8
263	263		Width = 128
264	264		Caption = 'Led1ToggleBox'
265	265		OnChange = Led1ToggleBoxChange
266	266		TabOrder = 1
267	267		end
268	268		object Led3ToggleBox: TToggleBox
269	269		Left = 8
270	270		Height = 24
271	271		Top = 56
272	272		Width = 128
273	273		Caption = 'Led3ToggleBox'
274	274		OnChange = Led3ToggleBoxChange
275	275		TabOrder = 2
276	276		end
277	277		object Led4ToggleBox: TToggleBox
278	278		Left = 8
279	279		Height = 24
280	280		Top = 80
281	281		Width = 128
282	282		Caption = 'Led4ToggleBox'
283	283		OnChange = Led4ToggleBoxChange
284	284		TabOrder = 3
285	285		end
286	286		object Led5ToggleBox: TToggleBox
287	287		Left = 8
288	288		Height = 24
289	289		Top = 104
290	290		Width = 128
291	291		Caption = 'Led5ToggleBox'
292	292		OnChange = Led5ToggleBoxChange
293	293		TabOrder = 4
294	294		end
295	295		object Led6ToggleBox: TToggleBox
296	296		Left = 8
297	297		Height = 24
298	298		Top = 128
299	299		Width = 128
300	300		Caption = 'Led6ToggleBox'
301	301		OnChange = Led6ToggleBoxChange
302	302		TabOrder = 5
303	303		end
304	304		object Shape1: TShape
305	305		Left = 144
306	306		Height = 18
307	307		Top = 12
308	308		Width = 16
309	309		Shape = stCircle
310	310		end
311	311		object Shape2: TShape
312	312		Left = 144
313	313		Height = 18
314	314		Top = 34
315	315		Width = 16
316	316		Shape = stCircle
317	317		end
318	318		object Shape3: TShape
319	319		Left = 144
320	320		Height = 18
321	321		Top = 58
322	322		Width = 16
323	323		Shape = stCircle
324	324		end
325	325		object Shape4: TShape
326	326		Left = 144
327	327		Height = 18
328	328		Top = 82
329	329		Width = 16
330	330		Shape = stCircle
331	331		end
332	332		object Shape5: TShape
333	333		Left = 144
334	334		Height = 18
335	335		Top = 106
336	336		Width = 16
337	337		Shape = stCircle
338	338		end
339	339		object Shape6: TShape
340	340		Left = 144
341	341		Height = 18
342	342		Top = 130
343	343		Width = 16
344	344		Shape = stCircle
345	345		end
346	346		object Shape7: TShape
347	347		Left = 144
348	348		Height = 18
349	349		Top = 158
350	350		Width = 16
351	351		Shape = stCircle
352	352		end
353	353		object Button1: TButton
354	354		Left = 8
355	355		Height = 25
356	356		Top = 151
357	357		Width = 64
358	358		Caption = 'Buzzer'
359	359		OnMouseDown = Button1MouseDown
360	360		OnMouseUp = Button1MouseUp
361	361		TabOrder = 6
362	362		end
363	363		object ApplicationProperties1: TApplicationProperties
364	364		OnIdle = ApplicationProperties1Idle
365	365		left = 72
366	366		top = 152
367	367		end
368	368		end
369	369		```
370	370
371	371		### Main
372	372
373	373		``` pascal
374	374		program berryclipdemo;
375	375
376	376		{$mode objfpc}{$H+}
377	377
378	378		uses
379	379		{$IFDEF UNIX}{$IFDEF UseCThreads}
380	380		cthreads,
381	381		{$ENDIF}{$ENDIF}
382	382		Interfaces, // this includes the LCL widgetset
383	383		Forms, Unit1, pi_io_unit, uberryclip, uraspberrypi
384	384		{ you can add units after this };
385	385
386	386		{$R *.res}
387	387
388	388		begin
389	389		RequireDerivedFormResource := True;
390	390		Application.Initialize;
391	391		Application.CreateForm(TForm1, Form1);
392	392		Application.Run;
393	393		end.
394	394		```
395	395
396	396		### Board
397	397
398	398		#### uberryclip.pas
399	399
400	400		``` pascal
401	401		unit uberryclip;
402	402
403	403		{$mode objfpc}{$H+}
404	404
405	405		interface
406	406
407	407		uses
408	408		Classes, SysUtils,
409	409		uRaspberrypi;
410	410		type
411	411
412	412		{ TBerryClip }
413	413
414	414		TBerryClip = class
415	415		private
416	416		RaspBerryPi : TRaspBerryPi;
417	417		public
418	418		constructor Create;
419	419		procedure SetLedOn( led_no :integer );
420	420		procedure SetLedOff( led_no :integer );
421	421		procedure SetBuzzerOn;
422	422		procedure SetBuzzerOff;
423	423		function ReadSwitch:boolean;
424	424		destructor Destroy; override;
425	425		end;
426	426		implementation
427	427
428	428		{ TBerryClip }
429	429
430	430		constructor TBerryClip.Create;
431	431		begin
432	432		RaspBerryPi := TRaspBerryPi.Create;
433	433		RaspBerryPi.SetGpioPinOutput(GPIO4); // Led 1
434	434		RaspBerryPi.SetGpioPinOutput(GPIO9); // Led 2
435	435		RaspBerryPi.SetGpioPinOutput(GPIO10);// Led 3
436	436		RaspBerryPi.SetGpioPinOutput(GPIO11);// Led 4
437	437		RaspBerryPi.SetGpioPinOutput(GPIO17);// Led 5
438	438		RaspBerryPi.SetGpioPinOutput(GPIO22);// Led 6
439	439		RaspBerryPi.SetGpioPinInput(GPIO7); // Switch
440	440		RaspBerryPi.SetGpioPinOutput(GPIO8); // Buzzer
441	441		end;
442	442
443	443		procedure TBerryClip.SetLedOn(led_no: integer);
444	444		begin
445	445		case led_no of
446	446		1 : RaspBerryPi.SetGpioBit(GPIO4);
447	447		2 : RaspBerryPi.SetGpioBit(GPIO17);
448	448		3 : RaspBerryPi.SetGpioBit(GPIO22);
449	449		4 : RaspBerryPi.SetGpioBit(GPIO10);
450	450		5 : RaspBerryPi.SetGpioBit(GPIO9);
451	451		6 : RaspBerryPi.SetGpioBit(GPIO11);
452	452		end;
453	453		end;
454	454
455	455		procedure TBerryClip.SetLedOff(led_no: integer);
456	456		begin
457	457		case led_no of
458	458		1 : RaspBerryPi.ClearGpioBit(GPIO4);
459	459		2 : RaspBerryPi.ClearGpioBit(GPIO17);
460	460		3 : RaspBerryPi.ClearGpioBit(GPIO22);
461	461		4 : RaspBerryPi.ClearGpioBit(GPIO10);
462	462		5 : RaspBerryPi.ClearGpioBit(GPIO9);
463	463		6 : RaspBerryPi.ClearGpioBit(GPIO11);
464	464		end;
465	465
466	466		end;
467	467
468	468		procedure TBerryClip.SetBuzzerOn;
469	469		begin
470	470		RaspBerryPi.SetGpioBit(GPIO8);
471	471		end;
472	472
473	473		procedure TBerryClip.SetBuzzerOff;
474	474		begin
475	475		RaspBerryPi.ClearGpioBit(GPIO8);
476	476		end;
477	477
478	478		function TBerryClip.ReadSwitch: boolean;
479	479		begin
480	480		result := RaspBerryPi.GetGpioBit(GPIO7);
481	481		end;
482	482
483	483		destructor TBerryClip.Destroy;
484	484		begin
485	485		RaspBerryPi.Free;
486	486		inherited Destroy;
487	487		end;
488	488
489	489		end.
490	490		```
491	491
492	492		#### uraspberrypi.pas
493	493
494	494		``` pascal
495	495		unit uraspberrypi;
496	496
497	497		{$mode objfpc}{$H+}
498	498
499	499		interface
500	500
501	501		uses
502	502		Classes, SysUtils, pi_io_unit, dialogs;
503	503
504	504		const
505	505
506	506		GPIO4 = 4;
507	507		GPIO7 = 7;
508	508		GPIO8 = 8;
509	509		GPIO9 = 9;
510	510		GPIO10= 10;
511	511		GPIO11= 11;
512	512		GPIO17= 17;
513	513		GPIO22= 22;
514	514
515	515		type
516	516
517	517		{ TRaspBerryPi }
518	518
519	519		TRaspBerryPi = class
520	520		private
521	521		io_port: T_IO_Port;
522	522		public
523	523		constructor Create;
524	524		procedure ClearGpioBit(no:byte);
525	525		function GetGpioBit(no:byte):boolean;
526	526		procedure SetGpioBit(no:byte);
527	527		procedure SetGpioPinInput( no:byte);
528	528		procedure SetGpioPinOutput( no:byte);
529	529		destructor Destroy; override;
530	530		end;
531	531
532	532		implementation
533	533
534	534		{ TRaspBerryPi }
535	535
536	536		constructor TRaspBerryPi.Create;
537	537		begin
538	538		if not MapIo
539	539		then ShowMessage('Error mapping gpio')
540	540		else
541	541		begin
542	542		io_port := T_IO_Port.Create;
543	543		io_port.f_gpio := CreatePort(GPIO_BASE);
544	544		end ;
545	545		end;
546	546
547	547		procedure TRaspBerryPi.ClearGpioBit(no: byte);
548	548		begin
549	549		io_port.ClearBit(no);
550	550		end;
551	551
552	552		function TRaspBerryPi.GetGpioBit(no: byte): boolean;
553	553		begin
554	554		result := io_port.GetBit(no);
555	555		end;
556	556
557	557		procedure TRaspBerryPi.SetGpioBit(no: byte);
558	558		begin
559	559		io_port.SetBit(no);
560	560		end;
561	561
562	562		procedure TRaspBerryPi.SetGpioPinInput(no: byte);
563	563		begin
564	564		io_port.SetPinMode(no,INPUT);
565	565		end;
566	566
567	567		procedure TRaspBerryPi.SetGpioPinOutput(no: byte);
568	568		begin
569	569		io_port.SetPinMode(no,OUTPUT);
570	570		end;
571	571
572	572		destructor TRaspBerryPi.Destroy;
573	573		begin
574	574		io_port.ClearBit(GPIO4);
575	575		io_port.ClearBit(GPIO9);
576	576		io_port.ClearBit(GPIO10);
577	577		io_port.ClearBit(GPIO11);
578	578		io_port.ClearBit(GPIO17);
579	579		io_port.ClearBit(GPIO22);
580	580		io_port.ClearBit(GPIO8);
581	581		UnMapIo(io_port);
582	582		io_port.free;
583	583		inherited Destroy;
584	584		end;
585	585
586	586		end.
587	587		```
588	588
589	589		#### pi_io_unit.pas
590	590
591	591		``` pascal
592	592		unit pi_io_unit;
593	593		// This code is tested only RPI2B Processor
594	594		{$mode objfpc}{$H+}
595	595
596	596		interface
597	597
598	598		uses
599	599		Classes, SysUtils, Unix, BaseUnix;
600	600
601	601		const
602	602		BCM2709_PBASE= $3F000000; // Peripheral Base in Bytes (RPI2B Processor)
603	603		// BCM2708_PBASE= $20000000; // Peripheral Base (maybe RPI1 )
604	604		REG_GPIO = BCM2709_PBASE div $1000; // $3F000 ;
605	605		PAGE_SIZE = $1000;
606	606
607	607		GPIO_BASE = (REG_GPIO + $200);
608	608
609	609		INPUT = 0;
610	610		OUTPUT = 1;
611	611
612	612		GPSET = $1C; // GPIO Pin Output Set
613	613		GPCLR = $28; // GPIO Pin Output Clear
614	614		GPLEV = $34; // GPIO Pin Level
615	615
616	616		type
617	617
618	618		{ T_IO_Port }
619	619
620	620		T_IO_Port = class
621	621		private
622	622		public
623	623		f_gpio: PLongWord;
624	624		procedure SetPinMode(a_io_pin, a_mode: byte);
625	625		function GetBit(a_io_pin : byte):boolean;inline;
626	626		procedure ClearBit(a_io_pin : byte);inline;
627	627		procedure SetBit(a_io_pin : byte);inline;
628	628		end;
629	629
630	630		function MapIo:boolean;// creates io mapping
631	631		procedure UnMapIo(a_Map: T_IO_Port);// close io
632	632		function CreatePort(PortGpio: LongWord): PLongWord;
633	633
634	634		implementation
635	635
636	636		var
637	637		fd: integer;// /dev/mem file handle
638	638
639	639		function MapIo: boolean;
640	640		begin
641	641		result := true;
642	642		fd := fpopen('/dev/mem', O_RdWr or O_Sync);
643	643		if fd < 0 then result := false; // unsuccessful mapping
644	644		end;
645	645
646	646		procedure UnMapIo( a_Map: T_IO_Port);
647	647		begin
648	648		if a_Map.f_gpio <> nil then
649	649		begin
650	650		fpMUnmap(a_Map.f_gpio, PAGE_SIZE);
651	651		a_Map.f_gpio := nil;
652	652		end;
653	653		end;
654	654
655	655		function CreatePort(PortGpio: LongWord): PLongWord;
656	656		begin
657	657		result := FpMmap(nil, PAGE_SIZE, PROT_READ or PROT_WRITE, MAP_SHARED, fd, PortGpio);
658	658		end;
659	659
660	660		procedure T_IO_Port.SetPinMode(a_io_pin, a_mode: byte);
661	661		var
662	662		fSel, shift : byte;
663	663		iof : PLongWord;
664	664		begin
665	665		fSel := (a_io_pin div $A)*4 ;
666	666		shift := (a_io_pin mod $A)*3 ;
667	667		iof := Pointer(LongWord(Self.f_gpio)+fSel);
668	668		case a_mode of
669	669		INPUT : iof^ := iof^ and ($FFFFFFFF - (7 shl shift));
670	670		OUTPUT : iof^ := iof^ and ($FFFFFFFF - (7 shl shift)) or (1 shl shift);
671	671		end;
672	672		end;
673	673
674	674		procedure T_IO_Port.SetBit(a_io_pin : byte);
675	675		var
676	676		iof : PLongWord;
677	677		begin
678	678		iof := Pointer(LongWord(Self.f_gpio) + GPSET + (a_io_pin shr 5) shl 2);
679	679		iof^ := 1 shl a_io_pin;
680	680		end;
681	681
682	682		procedure T_IO_Port.ClearBit(a_io_pin : byte);
683	683		var
684	684		iof : PLongWord;
685	685		begin
686	686		iof := Pointer(LongWord(Self.f_gpio) + GPCLR + (a_io_pin shr 5) shl 2);
687	687		iof^ := 1 shl a_io_pin;
688	688		end;
689	689
690	690		function T_IO_Port.GetBit(a_io_pin : byte):boolean;
691	691		var
692	692		iof : PLongWord;
693	693		begin
694	694		result := true;
695	695		iof := Pointer(LongWord(Self.f_gpio) + GPLEV + (a_io_pin shr 5) shl 2);
696	696		if (iof^ and (1 shl a_io_pin)) = 0 then result := false;
697	697		end;
698	698		end.
699	699		```
700	700
701	701		---
702	702		From the Free Pascal wiki, page "Raspberry Pi : BerryClip", as it stood on 2020-02-23 after a change by Trev, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).

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