Part Number:TMS320F28069
Tool/software: Code Composer Studio
Hello -
I'm testing with SCI bootloader on the F28069. I have CCS 6.2 loaded on my Windows 7 laptop.
I'm monitoring the SCI Tx and Rx lines and I see some unusual behavior occasionally.
Most of my testing has been successful. I send the 0x41 (A) to the F28069 after powering up with GPIO34=1 and GPIO37=0. It responds with another 0x41 and then I continue on with the AA... 08... etc.
However, A few times I have seen the F28069 respond with a 0x41 followed almost immediately by one or more 0x00 bytes. I've attached a screenshot of my oscilloscope output. The green is the RX line into the F28069 and the blue signal is the TX line response back out of the F28069.
I'm trying to understand where these 0x00s are coming from. I don't know whether the autobaud is jumping out of SCI mode and into flash after what seems like a successful autobaud, jumping to RAM for some mysterious reason or if it is sending the 0x00 bytes while still in boot ROM code.
Is there a way to step through the boot ROM code using the CCS debugger? I know how to load a program and debug from the first part of main(), but in this case I need the code to break at bootup and allow me to step through the ROM. Then, perhaps I can identify exactly where the 0x00 is getting loaded into the TX buffer and get this straightened out.
Thank-you!