Epiphany SDK 2015.1

This text describes the changes that went into eSDK 2015.1 and the companion Ubuntu images.

Highlights in this release:

1. Thermal improvements:

• You no longer need a fan if you just want to try the board out.
• We have taken several measures to reduce power consumption. The Epiphany chip-clock is now disabled when the chip is unused. Clock-gating is enabled by default. The unused north, west and south e-links are disabled.
• In the Ubuntu images we have added a thermal daemon that will force the Epiphany off if temperature gets too high. Disabling the Epiphany while another program is accessing the Epiphany can result in a hard system lockup, but there is no risk that any components get damaged.

2. Redesign of e-Link FPGA code

• Bandwidth is >3 higher for writes from ARM to Epiphany.

Ubuntu image changes

• Hostname: "parallella." (notice trailing period) or "parallella.local", depending on your operating system.
• IP address: The IP address will be acquired from DHCP. 10.11.12.13 will be used as fallback.
• Username: parallella
• Password: parallella

On first boot give it a couple of minutes to generate new SSH server keys before you try to connect to the board. We advise you to change the default password like so:

$ ssh parallella@parallella.
parallella@parallella's password: [Enter parallella]
parallella@parallella:~$ passwd
Changing password for parallella.
(current) UNIX password: [Enter parallella]
Enter new UNIX password: [Enter new password]
Retype new UNIX password: [Enter new password]
Password changed
parallella@parallella:~$ logout

Thermal daemon

To ensure the system does not get too hot a thermal daemon is included in the new Ubuntu images. The daemon monitors the Zynq temperature sensor (XADC). Should the temperature rise above the allowed range, the daemon will shut the Epiphany chip down. The default upper limit is set to 70°C. Notice that disabling the Epiphany chip while another program is accessing the Epiphany is likely to result in the board freezing. So if you see lockups when the system is under load, this is a probable cause.

In Linux you can monitor the temperature with xtemp from the parallella-utils package.

$ ssh -Y parallella@parallella
parallella@parallella:~$ sudo apt-get install parallella-utils
parallella@parallella:~$ xtemp

On Windows and Mac OS X you can use the ztemp.sh script in this forum post: http://www.parallella.org/forums/viewtopic.php?t=930&p=5976#p6242

Transitory quirks in this release

The quirks listed in this section will be properly fixed in a forthcoming release.

e-hal

In this release it is mandatory to call e_reset_system() before you access the Epiphany chip. Failing to do so will result in a hard system freeze.

We also recommend that you call e_finalize() when you are done. This will disable the Epiphany chip which saves some power and reduces heat.

e-server

e-server does not call e_reset_system(). Therefore you can only start it when another program already is connected to the Epiphany.