今天看了一个文档，读bq7835的dataflash，如下
/*Read Block Format e.g.
Frame1:Start + Device Address :0x16 + ManufactoryBlockAccess : 0x44 + Data Length: 0x02 +DataFlash Address:0x00 , 0x40 + Checksum: 0xAB + End
Frame2:Start + Device Address: 0x16 + ManufactoryBlockAccess:0x44 + Re-Start + Device Address:0x17 + Data Length:0x22(DataFlash Address 2bytes+32bytes data) + 34bytes Data + Checksum:0x85 + End
...
Send Frame2 Again To Get The Next 32 Bytes Data
*/
请问一下：
1、Frame1最后的 Checksum: 0xAB是怎么计算的？
2、Frame2最后的Checksum:0x85又是怎么计算的？
麻烦有人帮忙解答一下，非常感谢！