SAM9.md

Making embedded Linux computer

Ball diameter of the 217-LFBGA package is 0.4 mm and distance between adjacent balls is 0.8 mm.
I used 0.36 mm pads
Manufacturer needs to be able to make a via that fits in about 0.8 mm space
this distance includes includes via drill diameter, two times the annular ring around the via and two times the minimum distance between via and trace
iTead's four layer board has
- minimum via drill diameter of 0.3 mm,
- minimum annular ring width of 0.15 mm and
- minimum 0.15 mm between via and trace.

0.3 + 20.15 + 20.15 = 0.9mm
This adds up to 0.9 mm which means that minimum sized via can't fit between the BGA balls.

Minimum design rules are
- 5 mil trace clearance, (0.127mm)
- 5 mil trace width, (0.127mm)
- 10 mil drill size, and (0.254mm)
- 4 mil annular ring. (0.1016)
0.254 + 20.1016 + 20.127 = 0.7112mm

Board	Processor	Core	Architecture	Package
LinuxStamp	AT91RM9200	??	ARMv9	non-BGA
Linuxstamp II	AT91SAM9260	ARM9E-S	ARMv9	217-ball LFBGA and 208-pin QFP

AT91SAM9 AT91SAM9XE using ARM926EJ-S cores

SAM A5 ARM Cortex-A5 core

SAMA5D2
- SAMA5D26 - BGA 289, 14x14, 0.8mm pitch
- SAMA5D21 - BGA 196, 11x11, 0.75mm pitch
SAMA5D3
SAMA5D4

Atmel MPU list Lowest Cortex-A5 : SAMA5D21 - BGA 196, 11x11, 0.75mm pitch : SAMA5D26 - BGA 289, 14x14, 0.8mm pitch

Lowest SAM9 (ARM926EJ-S) : SAM9260 - BGA 217, 15x15, 0.8mm pitch; QFP 208, 28x28, 0.5mm pitch

Board	Processor	Family	Core	Architecture	Package
LinuxStamp	AT91RM9200	??	??	??	non-BGA
Linuxstamp II	AT91SAM9260	ARM9E	ARM9E-S	?	217-ball LFBGA and 208-pin QFP
Henrik Embedded	AT91SAM9N12	ARM9E	ARM926EJ-S	ARMv5TEJ	217-ball LFBGA
ATSAMA5D2B-XULT	SAMA5D27B	Cortex-A5	SAM5D2	ARMv7-A	289-BGA 0.8mm pitch
AT91SAM9260-EK	AT91SAM9260	ARM9E	ARM926EJ-S	ARMv5TEJ	217-ball LFBGA and 208-pin QFP
AT91SAM9N12-EK	AT91SAM9N12	ARM9E	ARM926EJ-S	ARMv5TEJ	217-ball LFBGA