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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 298
UG585 (v1.11) September 27, 2016
Chapter 10: DDR Memory Controller
10.2.4 TrustZone
The DDR memory can be configured in 64 MB sections. Each section can be configured to be either
secure or non-secure. This configuration is provided via a system level control register.
•A 0 on a particular bit indicates a secure memory region for that particular memory segment.
•A 1 on a particular bit indicates a non-secure memory region for that particular memory
segment.
In the case of a non-secure access to a secure region, a DECERR response is returned back to the
master. For writes, the write data is masked out before being sent to the controller which results in
no actual writes occurring in the DRAM. On reads, the read data is all zeros on a TZ violation. For
more information on TrustZone see Programming ARM TrustZone Architecture on the Xilinx
Zynq-7000 All Programmable SoC (UG1019).
10.3 DDR Core and Transaction Scheduler (DDRC)
The DDRC is comprised of queues for pending read and write transactions and a scheduler that pops
off the queues and sends the next transaction to the DDR PHY. Between the DDRI and the DDRC,
there is arbitration logic to decide which transaction is sent to the DDRC next.
X-Ref Target - Figure 10-4
Figure 10-4: DDRC Block Diagram
UG585_c10_04_032012
DDR Interface
DDR Core
DDR PHY
Pending DDR
Transactions
Read
Request
Stage 1
Read
Arbiter
AXI Port Arbiter
Self-Coherent
and with DDR
Write
Request
Reads
Transaction
Scheduler
Optimization
Algorithms
Stage 2
Stage 3
DRAM R/W State
Open Bank State
Sequencer
DDR
DRAM
Device(s)
Writes
Write
Arbiter