ios ble OTA 分包发送

iOS中的OTA升级的时候,发送完启动指令和将要传输数据的指令之后,开始传输升级文件,由于蓝牙设备每次只能接受20字节,所以文件要分包发送:

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"OTA_20170126_双模_1" ofType:@"bin"];
                NSFileManager *manager =[NSFileManager defaultManager];
                NSData *data = [[NSData alloc] init];
                data = [manager contentsAtPath:filePath];
                NSLog(@"%ld",(unsigned long)[data length]);
                //返回的是小端16进制的数据,一定要转化成10进制的
                for (int i = 0; i < [data length]; i+=20) {
                    NSLog(@"%d",i);
                    if (i+20< [data length]) {
                        NSData *subData = [data subdataWithRange:NSMakeRange(i, 20)];
                        [[GTCBLEManager shared]writeFileData:subData];
//根据你硬件的要求设置时间 基本上小于5ms是不能的
                        usleep(6000);
                    }else if (i+20> [data length]){
//最后一包不足20   如果硬件有要求可以去补F
                        NSData *subData = [data subdataWithRange:NSMakeRange(i, 16)];
                        [[GTCBLEManager shared]writeFileData:subData];
                        usleep(6000);
}