{"id":833,"date":"2026-04-20T14:42:07","date_gmt":"2026-04-20T06:42:07","guid":{"rendered":"https:\/\/hsiang.cc\/?p=833"},"modified":"2026-04-20T14:44:28","modified_gmt":"2026-04-20T06:44:28","slug":"c-%e7%9a%84%e9%82%a3%e4%ba%9b%e7%9c%89%e8%a7%92%e8%a8%bb%e8%a7%a3%e8%a6%81%e5%af%ab%e3%80%8c%e7%82%ba%e4%bb%80%e9%ba%bc%e3%80%8d%ef%bc%8c%e4%b8%8d%e6%98%af%e3%80%8c%e5%81%9a%e4%bb%80%e9%ba%bc","status":"publish","type":"post","link":"https:\/\/hsiang.cc\/?p=833","title":{"rendered":"[C \u7684\u90a3\u4e9b\u7709\u89d2]\u8a3b\u89e3\u8981\u5beb\u300c\u70ba\u4ec0\u9ebc\u300d\uff0c\u4e0d\u662f\u300c\u505a\u4ec0\u9ebc\u300d"},"content":{"rendered":"

\u8a18\u5f97\u5f88\u4e45\u4ee5\u524d\uff0c\u6211\u5beb\u8a3b\u89e3\u7684\u65b9\u5f0f\u5927\u6982\u985e\u4f3c\u9019\u6a23\uff1a<\/p>\n

i++;  \/\/ i \u52a0 1<\/code><\/pre>\n
\u73fe\u5728\u60f3\u8d77\u4f86\uff0c\u89ba\u5f97\u5f88\u597d\u7b11\u3002
\n\u7576\u6642\u89ba\u5f97\u300c\u6709\u5beb\u8a3b\u89e3\u300d\u9019\u4ef6\u4e8b\u672c\u8eab\u5c31\u662f\u597d\u7fd2\u6163\uff0c
\n\u81f3\u65bc\u5beb\u4e86\u4ec0\u9ebc\u22ef\u22ef\u597d\u50cf\u4e0d\u592a\u91cd\u8981\uff1f<\/p>\n
\u5f8c\u4f86\u9032\u516c\u53f8\uff0c\u7b2c\u4e00\u6b21\u88ab senior \u5728 code review \u4e0a\u7559\u8a00\uff1a
\n\u300c\u9019\u500b\u8a3b\u89e3\u8ddf\u6c92\u5beb\u4e00\u6a23\u3002\u300d<\/p>\n
\u5f88\u76f4\u63a5\uff0c\u4f46\u4ed6\u8aaa\u5f97\u5c0d\u3002<\/p>\n
<\/p>\n
\n
\u5ee2\u8a71\u578b\u8a3b\u89e3\uff0c\u6bd4\u6c92\u6709\u66f4\u7cdf<\/h2>\n
\u6700\u5e38\u898b\u7684\u721b\u8a3b\u89e3\uff0c\u662f\u628a\u7a0b\u5f0f\u78bc\u7ffb\u8b6f\u6210\u4e2d\u6587\uff08\u6216\u82f1\u6587\uff09\uff1a<\/p>\n
\/\/ \u5c07 count \u52a0 1\ncount++;\n\n\/\/ \u6aa2\u67e5 buffer \u662f\u5426\u70ba NULL\nif (buffer == NULL) {\n    return -1;\n}\n\n\/\/ \u547c\u53eb uart_send \u767c\u9001\u8cc7\u6599\nuart_send(data, len);<\/code><\/pre>\n
\u9019\u4e9b\u8a3b\u89e3\u63d0\u4f9b\u4e86\u96f6\u984d\u5916\u8cc7\u8a0a<\/strong>\u3002<\/p>\n
\u7a0b\u5f0f\u78bc\u672c\u8eab\u5c31\u8aaa\u4e86\u300ccount \u52a0 1\u300d\u3001\u300c\u6aa2\u67e5 NULL\u300d\u3001\u300c\u547c\u53eb uart_send\u300d\u3002
\n\u4f60\u7684\u8a3b\u89e3\u53ea\u662f\u628a\u540c\u6a23\u7684\u4e8b\u60c5\u8aaa\u4e86\u5169\u904d\uff0c\u800c\u4e14\u9084\u8981\u82b1\u6642\u9593\u7dad\u8b77\u5b83\u3002<\/p>\n
\u66f4\u7cdf\u7684\u60c5\u6cc1\u662f\uff1a\u7a0b\u5f0f\u78bc\u6539\u4e86\uff0c\u4f46\u8a3b\u89e3\u5fd8\u8a18\u66f4\u65b0\uff0c
\n\u7136\u5f8c\u4e0b\u4e00\u500b\u4eba\uff08\u53ef\u80fd\u662f\u4e09\u500b\u6708\u5f8c\u7684\u4f60\uff09\u770b\u5230\u7684\u662f\u4e92\u76f8\u77db\u76fe\u7684\u8cc7\u8a0a\u3002<\/p>\n
\n
\u597d\u7684\u8a3b\u89e3\u5728\u8aaa\u300c\u70ba\u4ec0\u9ebc\u300d<\/h2>\n
\u7a0b\u5f0f\u78bc\u80fd\u544a\u8a34\u4f60\u300c\u505a\u4e86\u4ec0\u9ebc\u300d\uff0c\u4f46\u6c92\u8fa6\u6cd5\u544a\u8a34\u4f60\u300c\u70ba\u4ec0\u9ebc\u9019\u6a23\u505a\u300d\u3002<\/p>\n
\u9019\u624d\u662f\u8a3b\u89e3\u771f\u6b63\u7684\u50f9\u503c\u6240\u5728\u3002<\/p>\n
\/\/ \u274c \u8aaa\u505a\u4ec0\u9ebc\uff08\u7a0b\u5f0f\u78bc\u5df2\u7d93\u8aaa\u4e86\uff09\n\/\/ \u5ef6\u9072 100ms\ndelay_ms(100);\n\n\/\/ \u2705 \u8aaa\u70ba\u4ec0\u9ebc\n\/\/ \u7b49\u5f85\u96fb\u6e90\u7a69\u5b9a\uff0c\u898f\u683c\u66f8 p.23 \u6307\u51fa\u4e0a\u96fb\u5f8c\u9700\u81f3\u5c11 100ms \u624d\u80fd\u64cd\u4f5c\ndelay_ms(100);<\/code><\/pre>\n
\/\/ \u274c\n\/\/ \u91cd\u8a66\u4e09\u6b21\nfor (int i = 0; i < 3; i++) {\n    if (send_command(cmd) == 0) break;\n}\n\n\/\/ \u2705\n\/\/ \u786c\u9ad4\u5076\u767c NAK\uff0c\u539f\u56e0\u4e0d\u660e\uff0c\u5be6\u6e2c\u91cd\u8a66\u4e09\u6b21\u5167\u90fd\u80fd\u6210\u529f\n\/\/ TODO: \u5f85\u5ee0\u5546\u78ba\u8a8d\u6839\u672c\u539f\u56e0 (2024-03-15)\nfor (int i = 0; i < 3; i++) {\n    if (send_command(cmd) == 0) break;\n}<\/code><\/pre>\n
\u7b2c\u4e8c\u500b\u7248\u672c\uff0c\u4f60\u77e5\u9053\u9019\u500b retry \u4e0d\u662f\u96a8\u4fbf\u5beb\u7684\uff0c
\n\u662f\u56e0\u70ba\u6709\u500b\u771f\u5be6\u7684\u786c\u9ad4\u554f\u984c\uff0c\u800c\u4e14\u9084\u6709\u500b TODO \u63d0\u9192\u5f8c\u7e8c\u8981\u8ddf\u9032\u3002<\/p>\n
\u9019\u624d\u662f\u6709\u50f9\u503c\u7684\u8cc7\u8a0a\u3002<\/p>\n
\n
\u5e7e\u7a2e\u503c\u5f97\u5beb\u7684\u60c5\u6cc1<\/h2>\n
1. \u53cd\u76f4\u89ba\u7684\u5beb\u6cd5<\/h3>\n
\u770b\u8d77\u4f86\u300c\u5947\u602a\u300d\u4f46\u6709\u539f\u56e0\u7684\u7a0b\u5f0f\u78bc\uff0c\u4e00\u5b9a\u8981\u89e3\u91cb\uff1a<\/p>\n
\/\/ \u6545\u610f\u4e0d\u52a0 break \u2014 \u9019\u88e1\u9700\u8981 fall-through \u5230\u4e0b\u4e00\u500b case\ncase STATE_CONNECTING:\ncase STATE_RECONNECTING:\n    start_connection_timer();\n    break;<\/code><\/pre>\n
\/\/ \u7528 volatile \u8b80\u4e00\u6b21\u4f86\u6e05\u9664\u4e2d\u65b7 flag\uff0c\u4e0d\u80fd\u512a\u5316\u6389\u9019\u884c\nvolatile uint32_t dummy = UART->SR;\n(void)dummy;<\/code><\/pre>\n
\u6c92\u6709\u9019\u4e9b\u8a3b\u89e3\uff0c\u4e0b\u4e00\u500b\u4eba\u770b\u5230\u6703\u4ee5\u70ba\u662f bug\uff0c\u7136\u5f8c\u300c\u4fee\u6389\u300d\u5b83\u3002<\/p>\n
\n
2. \u8e29\u904e\u7684\u5751\u3001\u5df2\u77e5\u7684\u9650\u5236<\/h3>\n
\/\/ \u6ce8\u610f\uff1a\u9019\u500b\u51fd\u5f0f\u4e0d\u662f thread-safe\n\/\/ \u547c\u53eb\u524d\u5fc5\u9808\u5148\u53d6\u5f97 sensor_mutex\nint16_t sensor_get_temperature(void) {\n    ...\n}<\/code><\/pre>\n
\/\/ buf_size \u5fc5\u9808\u662f 4 \u7684\u500d\u6578\uff0c\u5426\u5247 DMA \u50b3\u8f38\u6703\u5c0d\u9f4a\u932f\u8aa4\n\/\/ \u9019\u500b\u9650\u5236\u4f86\u81ea\u786c\u9ad4\uff0c\u4e0d\u662f bug\nint dma_read(uint8_t *buf, size_t buf_size) {\n    ...\n}<\/code><\/pre>\n
\u9019\u7a2e\u8cc7\u8a0a\u85cf\u5728\u7a0b\u5f0f\u78bc\u88e1\uff0c\u6839\u672c\u770b\u4e0d\u51fa\u4f86\u3002
\n\u4f46\u5982\u679c\u4f60\u4e0d\u77e5\u9053\uff0c\u5c31\u6703\u8e29\u5230\u4e00\u6a23\u7684\u5751\u3002<\/p>\n
\n
3. \u53c3\u8003\u4f86\u6e90<\/h3>\n
\u5d4c\u5165\u5f0f\u958b\u767c\u5e38\u5e38\u8981\u67e5\u898f\u683c\u66f8\u3001\u61c9\u7528\u7b46\u8a18\uff0c
\n\u628a\u4f86\u6e90\u8a18\u4e0b\u4f86\uff0c\u4e4b\u5f8c\u67e5\u554f\u984c\u7701\u5f88\u591a\u6642\u9593\uff1a<\/p>\n
\/\/ \u4f9d\u7167 datasheet Table 5-3\uff0cADC \u8f49\u63db\u6642\u9593 = (SMPR + 12.5) cycles\n\/\/ STM32F4 Reference Manual RM0090, p.388\nuint32_t adc_sample_time = ADC_SAMPLETIME_84CYCLES;<\/code><\/pre>\n
\/\/ CRC \u8a08\u7b97\u65b9\u5f0f\u53c3\u8003 Modbus Application Protocol V1.1b3, Section 6\nuint16_t crc = modbus_crc16(frame, frame_len);<\/code><\/pre>\n
\n
4. \u66ab\u6642\u7684 workaround<\/h3>\n
\/\/ WORKAROUND: \u6a21\u7d44\u97cc\u9ad4 v1.2.3 \u6709 bug\uff0c\u9023\u7dda\u5f8c\u9700\u7b49 500ms \u624d\u80fd\u767c\u6307\u4ee4\n\/\/ \u9810\u8a08\u5ee0\u5546 v1.3.0 \u4fee\u5fa9\uff0c\u4fee\u5fa9\u5f8c\u53ef\u79fb\u9664\u6b64 delay\n\/\/ Ticket: #1234\ndelay_ms(500);<\/code><\/pre>\n
\u9019\u7a2e\u6700\u91cd\u8981\u3002<\/p>\n
\u6c92\u6709\u9019\u500b\u8a3b\u89e3\uff0c\u516d\u500b\u6708\u5f8c\u6c92\u4eba\u77e5\u9053\u9019\u500b delay \u80fd\u4e0d\u80fd\u62ff\u6389\uff0c
\n\u7d50\u679c\u5c31\u662f\u6c38\u9060\u7559\u5728\u90a3\u88e1\uff0c\u6c92\u4eba\u6562\u52d5\u3002<\/p>\n
\n
\u51fd\u5f0f\u7684 Header \u8a3b\u89e3<\/h2>\n
\u51fd\u5f0f\u5c64\u7d1a\u7684\u8a3b\u89e3\uff0c\u6211\u7fd2\u6163\u7528\u7c21\u5316\u7248\u7684 Doxygen \u683c\u5f0f\uff0c
\n\u4e0d\u7528\u5168\u90e8\u90fd\u5beb\uff0c\u4f46\u81f3\u5c11\u8aaa\u6e05\u695a\u300c\u9019\u500b\u51fd\u5f0f\u5728\u505a\u4ec0\u9ebc\u3001\u6709\u4ec0\u9ebc\u9650\u5236\u300d\uff1a<\/p>\n
\/**\n * \u5f9e\u611f\u6e2c\u5668\u8b80\u53d6\u6eab\u5ea6\n *\n * @param timeout_ms  \u7b49\u5f85\u903e\u6642\u6642\u9593\uff08\u6beb\u79d2\uff09\uff0c0 \u8868\u793a\u4e0d\u7b49\u5f85\n * @return            \u6eab\u5ea6\u503c\uff08\u651d\u6c0f x10\uff0c\u4f8b\u5982 235 \u4ee3\u8868 23.5\u00b0C\uff09\n *                    \u8ca0\u503c\u4ee3\u8868\u932f\u8aa4\u78bc\n *\n * @note \u547c\u53eb\u524d\u9700\u78ba\u4fdd sensor_init() \u5df2\u5b8c\u6210\n * @note \u4e0d\u662f thread-safe\uff0c\u591a\u57f7\u884c\u7dd2\u74b0\u5883\u9700\u81ea\u884c\u52a0\u9396\n *\/\nint16_t sensor_read_temperature(uint32_t timeout_ms);<\/code><\/pre>\n
\u91cd\u9ede\u662f @note<\/code>\uff0c\u628a\u547c\u53eb\u9650\u5236\u548c\u6ce8\u610f\u4e8b\u9805<\/strong>\u5beb\u6e05\u695a\u3002
\n\u9019\u4e9b\u624d\u662f\u8b93\u4f7f\u7528\u8005\u4e0d\u8e29\u5751\u7684\u95dc\u9375\u8cc7\u8a0a\u3002<\/p>\n
\n
\u4ec0\u9ebc\u6642\u5019\u4e0d\u8a72\u5beb\u8a3b\u89e3<\/h2>\n
\u9019\u500b\u4e5f\u5f88\u91cd\u8981\u3002<\/p>\n
\u5982\u679c\u4f60\u7684\u547d\u540d\u5920\u597d\uff0c\u5f88\u591a\u5730\u65b9\u6839\u672c\u4e0d\u9700\u8981\u8a3b\u89e3\uff1a<\/strong><\/p>\n
\/\/ \u274c \u547d\u540d\u721b\uff0c\u9760\u8a3b\u89e3\u88dc\u6551\nint x;  \/\/ \u96fb\u6c60\u96fb\u58d3\uff0c\u55ae\u4f4d mV\nx = read_adc_channel(ADC_CH_BATTERY);\n\n\/\/ \u2705 \u547d\u540d\u597d\uff0c\u4e0d\u9700\u8981\u8a3b\u89e3\nint battery_voltage_mv = read_adc_channel(ADC_CH_BATTERY);<\/code><\/pre>\n
\u5982\u679c\u4f60\u767c\u73fe\u81ea\u5df1\u5728\u5beb\u300c\u89e3\u91cb\u9019\u500b\u8b8a\u6578\u662f\u4ec0\u9ebc\u300d\u7684\u8a3b\u89e3\uff0c
\n\u901a\u5e38\u4ee3\u8868\u547d\u540d\u53ef\u4ee5\u518d\u60f3\u4e00\u4e0b\u3002<\/p>\n
\n
\u5f8c\u8a18<\/h2>\n
\u6211\u73fe\u5728\u9084\u662f\u5076\u723e\u6703\u5beb\u5ee2\u8a71\u578b\u8a3b\u89e3\u3002<\/p>\n
\u8d95\u9032\u5ea6\u7684\u6642\u5019\uff0c\u80fd\u52d5\u5c31\u597d\uff0c\u54ea\u6709\u6642\u9593\u60f3\u300c\u9019\u500b delay \u7684\u539f\u56e0\u662f\u4ec0\u9ebc\u300d\u3002<\/p>\n
\u4f46\u6211\u5b78\u5230\u7684\u662f\uff1a\u6700\u5c11\u4e5f\u8981\u5728 workaround \u548c\u53cd\u76f4\u89ba\u7684\u5730\u65b9\u5beb\u6e05\u695a<\/strong>\u3002
\n\u90a3\u4e9b\u5730\u65b9\u7684\u4e00\u884c\u8a3b\u89e3\uff0c\u53ef\u4ee5\u5e6b\u672a\u4f86\u7684\u4eba\uff08\u5305\u62ec\u81ea\u5df1\uff09\u7701\u6389\u597d\u5e7e\u500b\u5c0f\u6642\u7684 debug \u6642\u9593\u3002<\/p>\n
\u5176\u4ed6\u5730\u65b9\uff0c\u8207\u5176\u5beb\u5ee2\u8a71\uff0c\u4e0d\u5982.....\u5c31\u4e0d\u5beb\u5427\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u8a18\u5f97\u5f88\u4e45\u4ee5\u524d\uff0c\u6211\u5beb\u8a3b\u89e3\u7684\u65b9\u5f0f\u5927\u6982\u985e\u4f3c\u9019\u6a23\uff1a i++; \/\/ i \u52a0 1 \u73fe\u5728\u60f3\u8d77 … \u95b1\u8b80\u5168\u6587 →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[15],"tags":[926,912,922,582,928,924,919,925,910,927,923,917],"class_list":{"0":"post-833","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"hentry","6":"category-prog","7":"tag-clean-code","8":"tag-c","11":"tag-workaround","12":"tag-924","14":"tag-925","15":"tag-910","16":"tag-927","17":"tag-923","18":"tag-917"},"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/hsiang.cc\/index.php?rest_route=\/wp\/v2\/posts\/833","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hsiang.cc\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hsiang.cc\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hsiang.cc\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hsiang.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=833"}],"version-history":[{"count":2,"href":"https:\/\/hsiang.cc\/index.php?rest_route=\/wp\/v2\/posts\/833\/revisions"}],"predecessor-version":[{"id":839,"href":"https:\/\/hsiang.cc\/index.php?rest_route=\/wp\/v2\/posts\/833\/revisions\/839"}],"wp:attachment":[{"href":"https:\/\/hsiang.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=833"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hsiang.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=833"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hsiang.cc\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=833"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}