2 Questions about the Cortex A9 on ZYNQ ?

[gma-87]

hi

excuse me to post this question whitch is about the Cortex A9 

when i begin working with ZYNQ-7000 AP SoCs , with all version in this family, i still can't found any details of information on Xilinx or ARM website about :

1- the ZYNQ is based on " Dual ARM® Cortex™-A9 MPCore " , witch mean, we have tow CPU ( when i use Xillinux on Zedboard, or Petalinux, it's montionnaed on system command , 2 CPU ( CPU0 and CPU1), when i return to ARMv7 datasheet, i found that defeneltly there is processor ( independelly each of other " Falcon CPU" ), with L2 shared betenn those 2 processor or Core), BUT what i can't found, is the  Maximum Frequency  866 Mhz , is defined for each processor or for the both together ? , witch mean, when i run a standalone application on CPU0 ( only), i can't until to this max frequency, and if i run 2 different standalone application ( one for each processor), it mean, i can eachve 866 Mhz for each processor ?

2- the temperature ontionnaded on the datasheet of ZYNQ Soc AP 7000, for example, the Z-7020 , Commercial (0C to 85C)

it mean that when the internal temperature of ZYNQ, excced those value, ZYNQ is shutdown or it still working without alarm or mometaly stop of the system ( automaticelly), i talk without the use of XADC bloc design ( without activate it ) ?

sorry for this long description, but it's the result of anclearn specificatio on datasheet, i hope can found the good answer or those question

i appreciate for all help

Thank you 

[austin]

g,

1.  Yes, both cores operate at the same frequency, at the same time.  ARM A9, Cortex, etc. are all copyright ARM.  The core used is documented as A7 on their web pages, as you note.  Do not ask me why they market it and document it this way (mystery to me, too).

As each processor core has its own L1 cache, the two processors will operate at the same time, until such time as one must stall to wait for access to L2, OCM, or any shared memory.  Monitoring performance is always complicated in multiprocessor systems, but there are methods to do that.

2.  The temperature of the device is the junction temperature, which is the temperature within the silicon die of the Zynq itself.

There is no automatic over temperature shut down, but you could implement one yourself by using teh Sysmon in the programmable logic to measyre junction temperature, and the activate a shutdown if the temperature is exceeded (by commanding power supplies to shut off).

[gma-87]

hi austin,

thank, you so much for this answer whitch is so clear, just i want to confirm that the max frequency ( 667 Mhz ), on Cortex A9, is the same for each core, witch mean like i have 2 CPU with this frequency, o when i run 2 independed applicaion, one for each processor ( core), i can achieved 677 Mhz ?

thank you again

[austin · Accepted solution]

g,

Yes.

But, if the CPU requires access to memory in common, it will wait (at 667 MHz) until the resource is free, and the memory contents are loaded into L1 cache, where it will then be executing the instructions at 667 MHz, rather that waiting (at 667 MHz).