iOS Bluetooth-チェックサムの取得、Bluetooth指令データ構築例

チェックサムメソッドの取得

- (Byte)CalCheckSum2:(NSData *)data{
    Byte chksum = 0;
    Byte *byte = (Byte *)[data bytes];
    for (NSUInteger i = 0; i < [data length]; i++){
        chksum += byte[i];
    }
    return chksum;
}

私の需要:命令は13ビットbyte配列で、最後の1位は前の12ビットのチェックサムで、3、4位は時間(24時間制)時間と分が変換されたbyteバイトで、その他は固定的な命令です。私の構造方法は

//   
- (void)onTimeChargeByBlueWith:(NSString *)timeStr
{
    NSArray *array = [timeStr componentsSeparatedByString:@":"];
    
    Byte onTimeChargeOrder[13] = {0};
    onTimeChargeOrder[0] = 0xB9;
    onTimeChargeOrder[1] = 0x60;
    onTimeChargeOrder[2] = [self getByteWithIntString:array[0]];
    onTimeChargeOrder[3] = [self getByteWithIntString:array[1]];
    onTimeChargeOrder[4] = 0x00;
    onTimeChargeOrder[5] = 0x00;
    onTimeChargeOrder[6] = 0x00;
    onTimeChargeOrder[7] = 0x00;
    onTimeChargeOrder[8] = 0x00;
    onTimeChargeOrder[9] = 0x00;
    onTimeChargeOrder[10] = 0x00;
    onTimeChargeOrder[11] = 0x00;
    onTimeChargeOrder[12] = [self CalCheckSum2:[NSData dataWithBytes:onTimeChargeOrder length:12]];
    
    NSData *data = [NSData dataWithBytes:&onTimeChargeOrder length:sizeof(onTimeChargeOrder)];
    
    NSLog(@"  %@",data);
// data， peripheral writeValue 
//    [self.currPeripheral writeValue:data forCharacteristic:self.characteristic type:CBCharacteristicWriteWithResponse];
    
}

#pragma mark----------- ----------------

- (Byte)getByteWithIntString:(NSString *)intString
{
    int hourInt = [intString intValue];
    Byte hourByte[4]  ={0};
    hourByte[0] = (char)(hourInt >>24 & 0xff);
    hourByte[1] = (char)((hourInt >> 16) & 0xff);
    hourByte[2] = (char)((hourInt >> 8) & 0xff);
    hourByte[3] = (char)((hourInt) & 0xff);
    return (char)((hourInt) & 0xff);
}
//  
- (Byte)CalCheckSum2:(NSData *)data{
    Byte chksum = 0;
    Byte *byte = (Byte *)[data bytes];
    for (NSUInteger i = 0; i < [data length]; i++){
        chksum += byte[i];
    }
    return chksum;
}

最後の呼び出し方法

[self onTimeChargeByBlueWith:@"13:45"];

得られたデータは

2017-03-11 11:23:21.211 test0227[92358:2093146]