Microchip Technology SAM E70 Xplained Ultra, Руководство пользователя

Страница: 16 / 58

5.3 SDRAM and LCD Connections
The external bus interface (EBI) on SAM E71 Xplaned Ultra is controlled by the static memory controller
(SMC) and SDRAM controllers modules in the ATSAME70Q21B.
ATSAME70Q21B has on-die series termination on very I/O pin as shown in figure below.
Figure 5-2. On-Die Termination
The EBI is connected to the on-board SDRAM and the Xplained Pro Graphics connector. The following
figure shows how the SDRAM and LCD share the same sets of data pins, and displays the location of the
series termination resistors.
Figure 5-3. LCD and SDRAM
As the I/O pins have on-die series termination, the impedance of the drivers must be matched to the
impedance of the EBI tracks on the PCB using series resistors. The EBI tracks are routed as 50Ω on
SAM E70 Xplained Ultra. The clock and address lines are only driven by the ATSAME70Q21B, while the
data lines are driven by the ATSAME70Q21B and the on-board SDRAM.
Hardware Features
©
2019 Microchip Technology Inc.
DS70005389A-page 16