Recently our product using BF533 has a production failure rate at 75% which cannot startup, BF533 is Boot from external 256KB SRAM,by measuring the signals, we find the AMS0 comes out of BF533 is incorrect after initialization
We debug using GHS, and find the software stop at the startup even cannot enter int main( ), see the following for details.
So do you know which situation can cause such hardware breakpoint ?
for this issue, we finally find it has two way to solve it:
1. change HW: with Flash : M29W800DB70ZE6 cannot work while with M29W400DB70ZE6 or S29AL008J70BFI020 OK
2. change SW: register EBIU_AMBCTL0, which changes from 0X44146614 to 0X66146614
we use BF533 with Flash and SRAM connected, both are through the Data/Address BUS control, AMS0 is to control Flash while AMS1 to control SRAM, we check the SW difference, and it focus on register EBIU_AMBCTL0, which is 0X44146614 vs 0X66146614, it changes the write and read access time of Bank 1 (SRAM), 40ns to 60ns, although the issue solved, we still confused why this setup can solve the issue, would you please help to have a look?