ADAU1450 Sigma Studio Bug? Instruction cycles

Hello,

You are correct in thinking that the core frequency has something to do with the difference! The column in the compiler output labelled "Inst (cycles)" refers to the number of instructions that can be used in one sample period. Due to the fact that the ADAU1452 has double the core frequency rate, it can perform twice as many instructions as the ADAU1450.

The other differences, in the DM0 and DM1 columns, are due to the fact that the ADAU1452 has 40kWords of data memory, while the ADAU1450 has 8kWords.

Regards,

Tyler

Hello,

Let me add to Tyler's response.

Since the core rate is half it can process half the number of instructions. At 48kHz fs the 1452 can process 6144 instructions per sample period. The 1450 can process half that which is 3072 instructions. Now when you run at 96kHz you have to divide these numbers by two. So the 1452 can process 3072 instructions and the 1450 can process 1536 instructions. So looking at the compilation results of your project, In the 1452 the program is using 2252 instructions which is 74% of 3072 but in the 1450 it is 147% of 1536. So this program will not fit in a 1450 running at 96kHz.

The memory differences you have to know that there is much less memory in the 1450. DM0 and DM1 are 20K words each on the 1452 and 4K words each in the 1450. So when DM0 filled up the compiler shifted it over to DM1. So you see 100% usage of DM0 and 95% of DM1.

So I suggest you go over to the ADAU1451 which runs at 300MHz so you have the full number of cycles but has twice the memory, 8kwords for DM0 and DM1. So your program will compile and run fine on the ADAU1451 and you will save some costs.

Dave T