From Igloo Community
Hardware Design Guidelines
The purpose of these recommendations is to secure A9500-based customers projects by providing a list of high-level guidelines. You will find here tips and tricks to minimize surprises when designing Snowball based PCB derivatives.
- Don’t make any precipitate hardware changes to the Snowball baseline which would result in a dramatic misalignment of the low-level software.
- Use the Snowball approved list of components.
- Contact your A9500 distributor to drive you with the recommendations dedicated to your project.
- When starting new schematics and PCB, always start from the Snowball PDK baseline.
- When it makes sense for the project, the baseline should be extended to the Calao-systems’ tablet-kit, built upon Snowball + MOB-SKY-S9500-AVI and DAB-SKY-S9500-GPI-C01 expansion boards + ADB display adapter board.
- Have your schematics and layout reviewed by ST-Ericsson partners: A9500 Distributors or Calao-systems.
Flashing the board
- The A9500’s USB interface is the sole one supported by our flashing tools in a Snowball configuration and must be available for this purpose.
- The boot sequence is fixing the supply outputs from the AB8500. Swapping supply outputs could result in non bootable boards.
- The 2 decoupling capacitors for VrefDDRCA and VrefDDRDQ need to be changed from 100nF to 4.7nF.
- Use only qualified LP-DDR2 memories
Peripherals on USB OTG interface
- Preferably avoid connecting expansion devices through that interface. Use FSMC instead.
Peripherals on FSMC bus
- Preferably reuse the same devices and memory mapping as in hardware baselines or in previous projects in order to leverage on existing drivers and initialization sequence.
- Up to two device or feature can be supported on the FSMC.
- The Ethernet is already supported in Snowball.
- The ISP1763A, bringing additional two USB 2.0 host ports, is supported in the Snowball Tablet Development Kit.
- Preferably use the dedicated MIPI CSI YUV interface of A9500. A list of qualified cameras with associated driver is expected soon (example: OV5640).