需求

拿到手一款NXP的LPC824-DIP開(kāi)發(fā)板瓦糕，好簡(jiǎn)單喂柒，與我之前的LPC812 Mini Kit一樣簡(jiǎn)單：板載USB/UART轉(zhuǎn)換IC辣卒，甚至使用了轉(zhuǎn)換IC內(nèi)部的LDO做供電拧晕，預(yù)留SWD引腳紊扬。

離開(kāi)NXP之后蜒茄，NXP/Freescale的工程和工具鏈就摸的少了。STM32F072的JLINK-OB不知道是否可以支持LPC824餐屎，或者拿個(gè)FRDM的板載CMSIS-DAP來(lái)試試看檀葛。

bin2hex轉(zhuǎn)換

不過(guò)這么簡(jiǎn)單的MCU，可以采用編譯下載和printf的方式腹缩。我目前用的最多的還是mbed在線編譯器屿聋，它僅支持bin格式。而NXP推薦的FlashMagic只支持intel hex格式藏鹊。而bin2hex的方法雖然有許多種润讥，但是都嫌麻煩。Keil推薦的bin2hex早就落伍了盘寡，gcc的objcopy還需要記錄一大堆參數(shù)象对。

Python intelhex包

忽然想起Python有一個(gè)intelhex包，重來(lái)沒(méi)有用過(guò)宴抚，使用pip安裝了一下：

pip install intelhex

轉(zhuǎn)換下載

安裝完畢后勒魔，在Python\Scripts下可以直接訪問(wèn)幾個(gè)工具腳本：

> dir c:\Python27\Scripts\*hex*.py
 驅(qū)動(dòng)器 C 中的卷是 HP_HDD
 卷的序列號(hào)是 48F7-515A

 c:\Python27\Scripts 的目錄

2017/09/28  14:20             3,825 bin2hex.py
2017/09/28  14:20             4,684 hex2bin.py
2017/09/28  14:20             4,549 hex2dump.py
2017/09/28  14:20             2,857 hexdiff.py
2017/09/28  14:20             3,681 hexinfo.py
2017/09/28  14:20             6,214 hexmerge.py
               6 個(gè)文件         25,810 字節(jié)
               0 個(gè)目錄 210,940,616,704 可用字節(jié)

我們把mbed產(chǎn)生的bin文件轉(zhuǎn)換成hex格式。

allankliu@ALLANKLIU-HP C:\Users\allankliu\Downloads
> bin2hex.py -h
Bin2Hex convertor utility.
Usage:
    python bin2hex.py [options] INFILE [OUTFILE]

Arguments:
    INFILE      name of bin file for processing.
                Use '-' for reading from stdin.

    OUTFILE     name of output file. If omitted then output
                will be writing to stdout.

Options:
    -h, --help              this help message.
    -v, --version           version info.
    --offset=N              offset for loading bin file (default: 0).


allankliu@ALLANKLIU-HP C:\Users\allankliu\Downloads
> bin2hex.py mbed_blinky_LPC_LPC824.bin mbed_blinky_LPC_LPC824.hex

allankliu@ALLANKLIU-HP C:\Users\allankliu\Downloads
> hexinfo.py mbed_blinky_LPC_LPC824.hex
- file: 'mbed_blinky_LPC_LPC824.hex'
  data:
  - { first: 0x00000000, last: 0x00002AFF, length: 0x00002B00 }

我們可以看一下轉(zhuǎn)換后的hex文件菇曲。

allankliu@ALLANKLIU-HP C:\Users\allankliu\Downloads
> hex2dump.py mbed_blinky_LPC_LPC824.hex
0000  00 20 00 10 DD 00 00 00 ED 00 00 00 E5 00 00 00  |. ..............|
0010  00 00 00 00 00 00 00 00 00 00 00 00 51 DD FF EF  |............Q...|
0020  00 00 00 00 00 00 00 00 00 00 00 00 E7 00 00 00  |................|
0030  00 00 00 00 00 00 00 00 E9 00 00 00 EB 00 00 00  |................|
0040  ED 00 00 00 ED 00 00 00 00 00 00 00 ED 00 00 00  |................|
0050  ED 00 00 00 ED 00 00 00 00 00 00 00 ED 00 00 00  |................|
0060  ED 00 00 00 ED 00 00 00 ED 00 00 00 ED 00 00 00  |................|
0070  ED 00 00 00 ED 00 00 00 ED 00 00 00 ED 00 00 00  |................|
0080  ED 00 00 00 ED 00 00 00 ED 00 00 00 ED 00 00 00  |................|
0090  ED 00 00 00 ED 00 00 00 ED 00 00 00 00 00 00 00  |................|
00A0  ED 00 00 00 ED 00 00 00 ED 00 00 00 ED 00 00 00  |................|
00B0  ED 00 00 00 ED 00 00 00 ED 00 00 00 ED 00 00 00  |................|
00C0  05 48 85 46 00 F0 12 FB 00 F0 EE F8 00 F0 86 F8  |.H.F............|
00D0  00 48 00 47 E5 02 00 00 00 20 00 10 04 48 80 47  |.H.G..... ...H.G|
00E0  04 48 00 47 FE E7 FE E7 FE E7 FE E7 FE E7 00 00  |.H.G............|
00F0  39 08 00 00 C1 00 00 00 F8 B5 17 46 0E 46 05 46  |9..........F.F.F|
0100  00 2B 07 D0 10 46 58 43 44 19 E4 1B 20 46 B0 47  |.+...FXCD... F.G|
0110  A5 42 FA D1 28 46 08 38 F8 BD 38 B5 05 46 68 46  |.B..(F.8..8..FhF|
0120  05 70 0C 46 08 68 00 23 01 22 69 46 01 F0 92 FC  |.p.F.h.#."iF....|
0130  00 28 02 D0 00 20 C0 43 38 BD E0 68 40 1C E0 60  |.(... .C8..h@..`|
0140  28 46 38 BD 30 B5 0B 46 01 46 00 20 20 22 01 24  |(F8.0..F.F.  ".$|
0150  09 E0 0D 46 D5 40 9D 42 05 D3 1D 46 95 40 49 1B  |...F.@.B...F.@I.|
0160  25 46 95 40 40 19 15 46 52 1E 00 2D F1 DC 30 BD  |%F.@@..FR..-..0.|
0170  03 46 0B 43 9B 07 03 D0 09 E0 08 C9 12 1F 08 C0  |.F.C............|
0180  04 2A FA D2 03 E0 0B 78 03 70 40 1C 49 1C 52 1E  |.*.....x.p@.I.R.|
0190  F9 D2 70 47 42 1C 01 78 40 1C 00 29 FB D1 80 1A  |..pGB..x@..)....|
01A0  70 47 10 B5 00 22 00 E0 52 1C 83 5C 8C 5C A3 42  |pG..."..R..\.\.B|
01B0  01 D1 00 2B F8 D1 D8 B2 E1 B2 40 1A 10 BD 30 B5  |...+......@...0.|
01C0  05 46 00 20 03 46 00 E0 5B 1C 93 42 05 D2 EC 5C  |.F. .F..[..B...\|
01D0  C8 5C 20 1A 01 D1 00 2C F6 D1 30 BD 70 B5 05 4C  |.\ ....,..0.p..L|
01E0  05 4D 03 E0 20 68 00 19 80 47 24 1D AC 42 F9 D1  |.M.. h...G$..B..|
01F0  70 BD 00 00 94 2A 00 00 98 2A 00 00 02 46 70 B5  |p....*...*...Fp.|
0200  4A 40 D3 0F DB 07 40 00 2D D0 4A 00 2A D0 01 0E  |J@....@.-.J.*...|
...
2900  6F 72 6B 73 70 61 63 65 2F 62 6D 5F 77 72 61 70  |orkspace/bm_wrap|
2910  2F 31 33 38 34 2F 6D 62 65 64 2D 6F 73 2F 74 61  |/1384/mbed-os/ta|
2920  72 67 65 74 73 2F 54 41 52 47 45 54 5F 4E 58 50  |rgets/TARGET_NXP|
2930  2F 54 41 52 47 45 54 5F 4C 50 43 38 32 58 2F 67  |/TARGET_LPC82X/g|
2940  70 69 6F 5F 61 70 69 2E 63 00 00 00 2F 68 6F 6D  |pio_api.c.../hom|
2950  65 2F 61 72 6D 2F 6D 62 65 64 5F 6A 65 6E 6B 69  |e/arm/mbed_jenki|
2960  6E 73 2F 77 6F 72 6B 73 70 61 63 65 2F 62 6D 5F  |ns/workspace/bm_|
2970  77 72 61 70 2F 31 33 38 34 2F 6D 62 65 64 2D 6F  |wrap/1384/mbed-o|
2980  73 2F 42 55 49 4C 44 2F 6D 62 65 64 2F 54 41 52  |s/BUILD/mbed/TAR|
2990  47 45 54 5F 4C 50 43 38 32 34 2F 54 41 52 47 45  |GET_LPC824/TARGE|
29A0  54 5F 4E 58 50 2F 54 41 52 47 45 54 5F 4C 50 43  |T_NXP/TARGET_LPC|
29B0  38 32 58 2F 67 70 69 6F 5F 6F 62 6A 65 63 74 2E  |82X/gpio_object.|
29C0  68 00 00 00 2F 68 6F 6D 65 2F 61 72 6D 2F 6D 62  |h.../home/arm/mb|
29D0  65 64 5F 6A 65 6E 6B 69 6E 73 2F 77 6F 72 6B 73  |ed_jenkins/works|
29E0  70 61 63 65 2F 62 6D 5F 77 72 61 70 2F 31 33 38  |pace/bm_wrap/138|
29F0  34 2F 6D 62 65 64 2D 6F 73 2F 74 61 72 67 65 74  |4/mbed-os/target|
2A00  73 2F 54 41 52 47 45 54 5F 4E 58 50 2F 54 41 52  |s/TARGET_NXP/TAR|
2A10  47 45 54 5F 4C 50 43 38 32 58 2F 70 69 6E 6D 61  |GET_LPC82X/pinma|
2A20  70 2E 63 00 2F 68 6F 6D 65 2F 61 72 6D 2F 6D 62  |p.c./home/arm/mb|
2A30  65 64 5F 6A 65 6E 6B 69 6E 73 2F 77 6F 72 6B 73  |ed_jenkins/works|
2A40  70 61 63 65 2F 62 6D 5F 77 72 61 70 2F 31 33 38  |pace/bm_wrap/138|
2A50  34 2F 6D 62 65 64 2D 6F 73 2F 70 6C 61 74 66 6F  |4/mbed-os/platfo|
2A60  72 6D 2F 6D 62 65 64 5F 63 72 69 74 69 63 61 6C  |rm/mbed_critical|
2A70  2E 63 00 00 98 2A 00 00 C0 00 00 10 68 00 00 00  |.c...*......h...|
2A80  4C 0E 00 00 00 2B 00 00 28 01 00 10 E8 01 00 00  |L....+..(.......|
2A90  5C 0E 00 00 D9 E3 FF FF 00 00 00 00 00 00 00 00  |\...............|
2AA0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  |................|
2AB0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  |................|
2AC0  00 00 00 00 80 C3 C9 01 00 87 93 03 00 00 00 00  |................|
2AD0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  |................|
2AE0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  |................|
2AF0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  |................|

話說(shuō)回來(lái)冠绢，覺(jué)得HEX中帶有這么多的源碼字符串有些怪異，可能與mbed平臺(tái)內(nèi)調(diào)試需求有關(guān)聯(lián)常潮。但是最好有個(gè)編譯開(kāi)關(guān)能夠把這些沒(méi)有必要的調(diào)試信息給關(guān)閉弟胀。這在小資源MCU還蠻重要的。

下載測(cè)試

把HEX代碼下載后喊式，一開(kāi)始沒(méi)有任何動(dòng)靜孵户。想想可能是LED的GPIO配置不同，改動(dòng)代碼后岔留，重復(fù)了整合流程夏哭，綠色LED開(kāi)始閃爍，UART也有輸出了献联。好簡(jiǎn)單竖配！

#include "mbed.h"

DigitalOut myled(LED2); // Change LED1 to LED2 on LPC824-DIP board
Serial pc(D1, D2);

int main() {
    while(1) {
        myled = 1;
        wait(0.2);
        myled = 0;
        wait(0.2);
        pc.printf(".");
        printf("#");
    }
}

改進(jìn)余地

• Python intelhex不僅提供了命令行工具軟件何址，更重要的是可以實(shí)現(xiàn)批量的程序化定制，比如根據(jù)MCU的UID進(jìn)行部分代碼的加密进胯。
• LPC系列中用爪，8051/ARM7/Cortex-M3/M4/M0/M0+，無(wú)論哪種內(nèi)核胁镐，都可以直接使用串口的RTS等串口流控線來(lái)控制目標(biāo)MCU的RST/ISP引腳偎血，而且邏輯電平都是負(fù)電平。
• Python pyserial可以很容易地操控流控引腳盯漂，繼而操控RST/ISP來(lái)控制MCU的工作模式烁巫，可以用于自動(dòng)讀取UID，計(jì)算密鑰宠能，將密鑰hex與原始hex進(jìn)行合并，燒入固件磁餐，啟動(dòng)CRP代碼保護(hù)违崇，直至復(fù)位。
• 基于這些設(shè)計(jì)诊霹，可以實(shí)現(xiàn)主機(jī)端（包括PC/平板和手機(jī)）動(dòng)態(tài)更新MCU固件羞延，在同一硬件上實(shí)現(xiàn)固件的動(dòng)態(tài)功能變化。不過(guò)嵌入式系統(tǒng)往往不具備通用性脾还，即時(shí)代碼更新缺乏業(yè)務(wù)支點(diǎn)和市場(chǎng)需求伴箩。不過(guò)我個(gè)人覺(jué)得可以先拿通用遙控器來(lái)玩玩、試試鄙漏。話說(shuō)嗤谚，好古老的需求。