以下示例程序将展示如何使用gpio的动态链接库编写一个boRecord的驱动程序，并且展示如何使用这个程序，控制一个LED灯的亮灭。

1） 新建这个示例程序的顶层目录，并且用makeBaseApp.pl在新建目录中构建这个IOC程序程序框架：

root@orangepizero2:/usr/local/EPICS/program#  mkdir boDriver
root@orangepizero2:/usr/local/EPICS/program# cd boDriver/
root@orangepizero2:/usr/local/EPICS/program/boDriver# makeBaseApp.pl -t ioc boDriver
root@orangepizero2:/usr/local/EPICS/program/boDriver# makeBaseApp.pl -i -t ioc boDriver
Using target architecture linux-aarch64 (only one available)
The following applications are available:
    boDriver
What application should the IOC(s) boot?
The default uses the IOC's name, even if not listed above.
Application name?
root@orangepizero2:/usr/local/EPICS/program/boDriver# ls
boDriverApp  configure  iocBoot  Makefile

2) 进入boDriver/boDriverApp/src路径，编写驱动程序和对应的支持文件：

源程序devbo_driver.c：

root@orangepizero2:/usr/local/EPICS/program/boDriver/boDriverApp/src# cat devbo_driver.c
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <wiringPi.h> // GPIO的头文件

#include "alarm.h"
#include "dbDefs.h"
#include "dbAccess.h"
#include "recGbl.h"
#include "recSup.h"
#include "devSup.h"
#include "boRecord.h"
#include "epicsExport.h"


/* 使用的GPIO管脚 */
#define LED     6

static long init_record(dbCommon *pcommon);
static long write_bo(boRecord *prec);

bodset devBoGPIO = {
    {5, NULL, NULL, init_record, NULL},
    write_bo
};

static long init_record(dbCommon *pcommon)
{
    long status;
    // 初始化GPIO
    wiringPiSetup();
    // 设置LED管脚为输出模式
    pinMode(LED, OUTPUT)    ;


    /*Don't convert*/
    status = 2;
    return status;

} /* end init_record() */

static long write_bo(boRecord *prec)
{
    long status;

    // 将输出值写到LED对应的管脚
    digitalWrite(LED,prec->val);


    return(status);
}

epicsExportAddress(dset,devBoGPIO);

支持文件devbo_driver.dbd：

root@orangepizero2:/usr/local/EPICS/program/boDriver/boDriverApp/src# cat devbo_driver.dbd
device(bo,INST_IO,devBoGPIO, "bo gpio")

编写Makefile文件，添加以下两处内容：

# 添加
boDriver_SRCS += devbo_driver.c
boDriver_DBD += devbo_driver.dbd

# 添加这个IOC所需的支持库
boDriver_LIBS += wiringPi
wiringPi_DIR = /usr/lib

3） 编写数据库实例文件，进入boDriver/boDriverApp/Db目录

编一个名为bo_gpio的数据库实例文件：

record(bo, "$(USER):BO")
{
        field(ONAM, "LIGHT ON")
        field(ZNAM, "LIGHT OFF")
        field(DTYP, "bo gpio")
}

并且把以上文件名添加到同一路径下的Makefile中：

DB += bo_gpio.db

4） 回到顶层目录boDriver执行make命令进行编译：

root@orangepizero2:/usr/local/EPICS/program/boDriver# make
make -C ./configure install
make[1]: Entering directory '/usr/local/EPICS/program/boDriver/configure'
...
make[2]: Nothing to be done for 'install'.
make[2]: Leaving directory '/usr/local/EPICS/program/boDriver/iocBoot/iocboDriver'
make[1]: Leaving directory '/usr/local/EPICS/program/boDriver/iocBoot'

5) 进入启动目录boDriver/iocBoot/iocboDriver中，修改启动文件st.cmd：

#!../../bin/linux-aarch64/boDriver

#- You may have to change boDriver to something else
#- everywhere it appears in this file

< envPaths

cd "${TOP}"

## Register all support components
dbLoadDatabase "dbd/boDriver.dbd"
boDriver_registerRecordDeviceDriver pdbbase

## Load record instances
dbLoadRecords("db/bo_gpio.db","USER=GPIO")

cd "${TOP}/iocBoot/${IOC}"
iocInit

 6） 用以下命令启动这个IOC程序：

root@orangepizero2:/usr/local/EPICS/program/boDriver/iocBoot/iocboDriver# ../../bin/linux-aarch64/boDriver st.cmd
#!../../bin/linux-aarch64/boDriver
< envPaths
epicsEnvSet("IOC","iocboDriver")
epicsEnvSet("TOP","/usr/local/EPICS/program/boDriver")
epicsEnvSet("EPICS_BASE","/usr/local/EPICS/base")
cd "/usr/local/EPICS/program/boDriver"
## Register all support components
dbLoadDatabase "dbd/boDriver.dbd"
boDriver_registerRecordDeviceDriver pdbbase
## Load record instances
dbLoadRecords("db/bo_gpio.db","USER=GPIO")
cd "/usr/local/EPICS/program/boDriver/iocBoot/iocboDriver"
iocInit
Starting iocInit
############################################################################
## EPICS R7.0.7
## Rev. 2023-05-26T09:07+0000
## Rev. Date build date/time:
############################################################################
iocRun: All initialization complete
## Start any sequence programs
#seq sncxxx,"user=orangepi"
epics> dbl
GPIO:BO

用dbl命令，查看当前IOC中只加载了一个记录GPIO:BO。

7） 用同一局域网中安装了通道访问工具的另一台计算机对这个IOC进行访问：

用cainfo查看GPIO:BO的信息：

[root@main-machine blctrl]# cainfo GPIO:BO
GPIO:BO
    State:            connected
    Host:             orangepizero2:5064
    Access:           read, write
    Native data type: DBF_ENUM
    Request type:     DBR_ENUM
    Element count:    1

在指定的GPIO管脚上点亮LED：

[root@main-machine blctrl]# caput GPIO:BO 1
Old : GPIO:BO                        LIGHT OFF
New : GPIO:BO                        LIGHT ON

熄灭指定的GPIO管脚上LED：

[root@main-machine blctrl]# caput GPIO:BO 0
Old : GPIO:BO                        LIGHT ON
New : GPIO:BO                        LIGHT OFF

结论：通过在驱动程序源程序中添加GPIO的头文件并且使用GPIO的库函数，并且在Makefile中指定要链接的GPIO库文件名称和对应的路径。在EPICS IOC中能够使用GPIO管脚进行数字量的输入和输出。