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Wiki source code of Front I/O

Version 8.6 by Kevin Wiki on 2024/07/07 21:44
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1 (% class="row" %)
2 (((
3 (% class="col-xs-12 col-sm-8" %)
4 (((
5 = Pinout =
6
7 There is a single cable that controls four parts, each half side of I/O LED and center column of blue LEDs.
8
9 [[image:xserve io main cable and PCB pinout.drawio.png||alt="xserve io main cable pinout.drawio.png"]]
10
11 (% class="wikigeneratedid" %)
12 [[attach:xserve io main cable and PCB pinout.drawio.svg||target="_blank"]]
13
14 (% class="wikigeneratedid" %)
15 This cable allows us to communicate with 4 chips using two data lines, audio & service switch, case switch and (yet to be documented) compute LEDs
16
17 = How we got here =
18
19 Measure out the ground and power signals by comparing with other chips on board. E.g. we find [SAA1064T] datasheet, locate the GND (Vee) and 5V (Vcc) and measure connectivity (0 ohm resistance) between chip pins and cable pins. This gives us pins GND 2 & 8 and PWR 16 & 22.
20
21 We keep doing this for SCL & SDA pins on SAA1064T chip and find pins 14 & 15 and 20 & 21 are I2C clock and data pins for each chip.
22
23 == Finding i2c chip address ==
24
25 === SAA1064T ===
26
27 Reading the datasheet for SAA1064T chip we find that: "//This results in the corresponding valid addresses HEX 70, 72, 74 and 76 for writing and 71, 73, 75 and 77 for reading. All other addresses cannot be acknowledged by the circuit".// Giving us a clue what we are looking for, i2c addresses 0x70, 0x72 or 0x74.
28
29 === PCA9554 ===
30
31 asdf
32
33 === Code example finding i2c addresses ===
34
35 We can test the following addresses manually or use the following code snippet:
36
37 {{code language="C++"}}
38 /*I2C_scanner
39 This sketch tests standard 7-bit addresses.
40 Devices with higher bit address might not be seen properly.*/
41
42 #include <Wire.h>
43
44 void setup() {
45 Wire.begin();
46
47 Serial.begin(9600);
48 while (!Serial);
49 Serial.println("\nI2C Scanner");
50 }
51
52 void loop() {
53 byte error, address;
54 int nDevices;
55
56 Serial.println("Scanning...");
57
58 nDevices = 0;
59 for (address = 1; address < 127; address++ ) {
60 Wire.beginTransmission(address);
61 error = Wire.endTransmission();
62
63 if (error == 0) {
64 Serial.print("I2C device found at address 0x");
65 if (address < 16)
66 Serial.print("0");
67 Serial.print(address, HEX);
68 Serial.println(" !");
69
70 nDevices++;
71 }
72 else if (error == 4) {
73 Serial.print("Unknown error at address 0x");
74 if (address < 16)
75 Serial.print("0");
76 Serial.println(address, HEX);
77 }
78 }
79 if (nDevices == 0)
80 Serial.println("No I2C devices found\n");
81 else
82 Serial.println("done\n");
83
84 delay(5000);
85 }
86 {{/code}}
87
88 == i2c multiplexing with TCA9548 ==
89
90 We have two sets of chips, one for left and one for right where we have two different i2c chips on each side for controlling lights. Since the chips controlling their respective parts have the same address for each side, we can't distinguish them from each other. To handle this we use a i2c multiplexer to selectively communicate with one half at a time, switching TCA9548 between two different output ports.
91
92 === Code example finding i2c ports ===
93
94 To verify wiring, connection, output ports and device addresses run the following script:
95
96 {{code language="c++"}}
97 /**
98 * TCA9548 I2CScanner.ino -- I2C bus scanner for Arduino
99 *
100 * Based on https://playground.arduino.cc/Main/I2cScanner/
101 *
102 */
103
104 #include "Wire.h"
105
106 #define TCAADDR 0x70
107
108 void tcaselect(uint8_t i) {
109 if (i > 7) return;
110
111 Wire.beginTransmission(TCAADDR);
112 Wire.write(1 << i);
113 Wire.endTransmission();
114 }
115
116
117 // standard Arduino setup()
118 void setup()
119 {
120 while (!Serial);
121 delay(1000);
122
123 Wire.begin();
124
125 Serial.begin(9600);
126 Serial.println("\nTCAScanner ready!");
127
128 for (uint8_t t=0; t<8; t++) {
129 tcaselect(t);
130 Serial.print("TCA Port #"); Serial.println(t);
131
132 for (uint8_t addr = 0; addr<=127; addr++) {
133 if (addr == TCAADDR) continue;
134
135 Wire.beginTransmission(addr);
136 if (!Wire.endTransmission()) {
137 Serial.print("Found I2C 0x"); Serial.println(addr,HEX);
138 }
139 }
140 }
141 Serial.println("\ndone");
142 }
143
144 void loop()
145 {
146 }
147 {{/code}}
148
149 == SAA1064T data for driving center IO LED stack ==
150
151 Center IO stack is a stack of 24 LED's, 23 blue and 1 green for ethernet activity. These are duplicated next to each other and driven by each their SAA1064T chips. Earlier we found the i2c address and just by playing around figured out that 4 segments of 1 byte binary values are used to set ship register.
152
153 {{code language="C++"}}
154 void fillColumns() {
155 Serial.println("filling columns");
156 Wire.beginTransmission(saa1064);
157 Wire.write(1);
158 Wire.write(0x7F); // 127 - 1111111
159 Wire.write(0x7F); // 127 - 1111111
160 Wire.write(0x7F); // 127 - 1111111
161 Wire.write(0x1F); // 31 - 11111
162 Wire.endTransmission();
163
164 colsFilled = 1;
165 }
166 {{/code}}
167
168 (% class="wikigeneratedid" %)
169 ~-~- Here the last byte we send only is 5 bits since we only have 5 LEDs instead of 6 to address (total of 24). Also note that we start the transmission with a single bit. ~-~-
170
171 == Pinouts voltages from MLB ==
172
173 Powered off:
174
175 * PWR fail LED - 0.00 V
176 * UID LED - 4.5V
177 * OH/Fan fail LED - 4.72 V
178 * NIC1 LED - 0.8 - 2.6 V
179 * NIC2 LED - 2.95 V
180 * UID SW - 2.8V
181 * HDD LED - 0.00 V
182 * Power LED P3V3 - 0.00V
183 * Power LED - 0.00 V after unplug grows
184
185 Powered on:
186
187 * PWR tail LED - 3.47 V
188 * UID LED - 4.85V
189 * OH/Fan failed LED - 5 V
190 * NIC 1 LED - 1.2 - 2.9 V
191 * NIC 2 LED - 3.2 V
192 * UID SW - 3V
193 * HDD LED - 3 V
194 * Power LED P3V3 - 3.30V
195 * Power LED - 0.87 V
196
197 = Controlling top I/O LED =
198
199 On the top row we have the following input/output devices in order from left to right;
200
201 Left side:
202
203 * physical lock
204 * lock LED
205 * warning/service button
206 * warning/service LED
207 * locate button
208 * power LED (red & green)
209 * fan LED (red & green)
210 * temperature LED (red & green)
211 * compute LED (unknown)
212
213 Right side:
214
215 * power LED (red & green)
216 * fan LED (red & green)
217 * temperature LED (red & green)
218 * compute LED (unknown)
219 * lock switch
220
221 Each sides bank of LEDs are driven by each their PCA9554 shift register. The registers represent the following LEDs: (Note that Lock LED is only present for the LEFT side)
222
223 (% border="1" %)
224 |=(% scope="row" %)Register|1|2|3|4|5|6|7
225 |=Device|Power LED Green|Power LED Red|Fan LED Green|Fan LED Red|Temperature LED Green|Temperature LED Red|Lock LED
226
227 To control each LED we shift either a 0 to turn off or 1 to turn on. Since each device shares a single red/green LED (power LED green & power LED red) setting both to 1 at the same time will always leave it red. That is when power LED green and power LED red are both enabled, red always takes precedence.
228
229 Use following script to power LEDs one at a time:
230
231 {{code language="c++"}}
232 #include <PCA9554.h> // Load the PCA9554 Library
233
234 PCA9554 ioCon1(0x24); // Create an object at this address
235
236 uint8_t mapIO = 0b10000000;
237
238 void shiftL() {
239 mapIO = (mapIO << 1) | ((mapIO & 0x80) >> 7);
240 }
241
242 void write() {
243 Serial.println("writing to PCA9554 device");
244
245 for (int i = 0; i < 8; ++i) {
246 ioCon1.digitalWrite(i, (mapIO & (1 << i)) ? 0 : 1);
247 }
248 }
249
250 void setup()
251 {
252 Serial.begin(9600);
253 Serial.println("Setup");
254
255 ioCon1.portMode(ALLOUTPUT);
256 }
257
258 void loop()
259 {
260 write();
261 shiftL();
262
263 delay(500);
264 }
265 {{/code}}
266
267
268 Controlling middle IO strip
269
270 0 = 0000
271 1 (green) = 0001
272 2 = 0010
273 1 + 2 = 0011
274 3 = 0100
275
276
277 There are 4 words, each containing 7 data bits. They do not
278
279
280 = Controlling center LED columns =
281
282 There are a total of 4 banks of addressable LED's 12 each of the total 48.
283
284 |=Register Banks|=LEDs|=Count
285 |=Bank 1|1 2 4 6 8 10 12|7
286 |=Bank 2|3 5 7 9 11 13|6
287 |=Bank 3|14 16 18 20 22 23 24|7
288 |=Bank 4|15 17 19 21|4
289
290 Script for writing all permutations to display:
291
292 {{code language="c++"}}
293 #include "Wire.h" // enable I2C bus
294
295 byte saa1064 = 0x3B; // define the I2C bus address for our SAA1064 (pin 1 to GND) ****
296
297 void setup()
298 {
299 Wire.begin(); // start up I2C bus
300 }
301
302 void write(int value) {
303 Wire.beginTransmission(saa1064);
304 Wire.write(1);
305
306 Wire.write(value);
307 Wire.write(value);
308 Wire.write(value);
309 Wire.write(value);
310
311 Wire.endTransmission();
312 }
313
314 void loop() {
315 for (int value = 0; value < 127; value++) {
316 write(value);
317 delay(300);
318 }
319 }
320 {{/code}}
321
322 Since LED positions don't map sequentially with LED number we can't address them in 10-base form, but we can define each LED in binary and use OR operator to display LEDs we want.
323
324 {{code language="c++"}}
325 #include "Wire.h" // enable I2C bus
326
327 #define TCAADDR 0x70
328 byte saa1064 = 0x3B; // define the I2C bus address for our SAA1064
329
330 byte bank1;
331 byte bank2;
332 byte bank3;
333 byte bank4;
334
335 byte activityLED = 0b00000001;
336 byte leds[23][4] = {
337 {0b00000010, 0b00000000, 0b00000000, 0b00000000}, // 1
338 {0b00000000, 0b00000010, 0b00000000, 0b00000000}, // 2
339 {0b00000100, 0b00000000, 0b00000000, 0b00000000}, // 3
340 {0b00000000, 0b00000100, 0b00000000, 0b00000000}, // 4
341 {0b00001000, 0b00000000, 0b00000000, 0b00000000}, // 5
342 {0b00000000, 0b00001000, 0b00000000, 0b00000000}, // 6
343 {0b00010000, 0b00000000, 0b00000000, 0b00000000}, // 7
344 {0b00000000, 0b00010000, 0b00000000, 0b00000000}, // 8
345 {0b00100000, 0b00000000, 0b00000000, 0b00000000}, // 9
346 {0b00000000, 0b00100000, 0b00000000, 0b00000000}, // 10
347 {0b01000000, 0b00000000, 0b00000000, 0b00000000}, // 11
348 {0b00000000, 0b01000000, 0b00000000, 0b00000000}, // 12
349 {0b00000000, 0b00000000, 0b00000001, 0b00000000}, // 13
350 {0b00000000, 0b00000000, 0b00000000, 0b00000001}, // 14
351 {0b00000000, 0b00000000, 0b00000010, 0b00000000}, // 15
352 {0b00000000, 0b00000000, 0b00000000, 0b00000010}, // 16
353 {0b00000000, 0b00000000, 0b00000100, 0b00000000}, // 17
354 {0b00000000, 0b00000000, 0b00000000, 0b00000100}, // 18
355 {0b00000000, 0b00000000, 0b00001000, 0b00000000}, // 19
356 {0b00000000, 0b00000000, 0b00000000, 0b00001000}, // 20
357 {0b00000000, 0b00000000, 0b00010000, 0b00000000}, // 21
358 {0b00000000, 0b00000000, 0b00100000, 0b00000000}, // 22
359 {0b00000000, 0b00000000, 0b01000000, 0b00000000} // 23
360 };
361
362 void setup()
363 {
364 Serial.begin(9600);
365 Wire.begin(); // start up I2C bus
366
367 Serial.println("setting up ports");
368 }
369
370 void tcaselect(uint8_t i) {
371 if (i > 7) return;
372
373 Wire.beginTransmission(TCAADDR);
374 Wire.write(1 << i);
375 Wire.endTransmission();
376 }
377
378 void selectLeft() { tcaselect(2); }
379 void selectRight() { tcaselect(1); }
380
381 void write() {
382 Wire.beginTransmission(saa1064);
383 Wire.write(1);
384
385 Wire.write(bank1);
386 Wire.write(bank2);
387 Wire.write(bank3);
388 Wire.write(bank4);
389
390 Wire.endTransmission();
391 }
392
393 void resetBanks() {
394 bank1 = 0;
395 bank2 = 0;
396 bank3 = 0;
397 bank4 = 0;
398 }
399
400 void displayNumber(int number) {
401 bank1 = leds[number - 1][0];
402 bank2 = leds[number - 1][1];
403 bank3 = leds[number - 1][2];
404 bank4 = leds[number - 1][3];
405 }
406
407 void displayUpToNumber(int number) {
408 for (int i = 0; i < number; i++) {
409 bank1 = bank1 | leds[i][0];
410 bank2 = bank2 | leds[i][1];
411 bank3 = bank3 | leds[i][2];
412 bank4 = bank4 | leds[i][3];
413 }
414 }
415
416 void computeEthernetActivity() {
417 bank1 = bank1 | activityLED;
418 }
419
420 void loop() {
421 resetBanks();
422 delay(10);
423
424 displayUpToNumber(15);
425 computeEthernetActivity();
426
427 selectLeft();
428 write();
429 delay(2);
430
431 selectRight();
432 write();
433 delay(1000);
434 }
435 {{/code}}
436
437
438 = Missing pieces, TODO =
439
440 * how to control compute LED in top IO row
441 * control warning button LED
442
443
444 )))
445
446
447 (% class="col-xs-12 col-sm-4" %)
448 (((
449 {{box title="**Contents**"}}
450 {{toc/}}
451 {{/box}}
452
453 [[image:[email protected]]]
454 //Figure 1: [[Sea>>https://commons.wikimedia.org/wiki/File:Isle_of_Icacos_II.jpg]]//
455
456 [[image:[email protected]]]
457 //Figure 2: [[Waves>>https://commons.wikimedia.org/wiki/File:Culebra_-_Playa_de_Flamenco.jpg]]//
458
459
460
461
462
463
464
465 )))
466 )))