MSP430 Code Debugging & Bluetooth Communication Fix

I'm working on a project involving a Windows computer sending a 4x4 0s and 1s matrix to a MSP430FR2355 Launchpad through an HC-05 Bluetooth module, and also through a usb-SPI adapter. The matrix uses CRC16 checksums. The issue is that the code on the MSP side isn't sending back ACK/NACK bits to the computer code to indicate it's ready for transmission. The same problem is encountered with both the Bluetooth and SPI computer codes.

The specific problems I'm facing are:
- The ACK/NACK bits logic has been implemented, but it's not functioning as expected.
- I suspect there may be an MSP430 software error.

I'm currently using Code Composer Studio for debugging. I need a freelancer with:
- Extensive experience with MSP430 programming
- Proficient debugging skills
- Familiarity with Bluetooth and SPI communication
- Understanding of CRC16 checksums
- Understanding of XOR encryption

Your task will be to:
- Diagnose the software error
- Fix the communication issue
- Ensure the ACK/NACK logic works correctly