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Noko0
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Fingerprint data storage
Noko0   10/5/2013 10:08:53 AM
Fully in line...look for NVM not for SRAM. so rather look into M7 (which has both large quantity of embedded flash, and encryption capability). PS: it would be worth to have floor plan analysis of M7 as well, and get evaluation of technology used and embedded flash size.

jamescpwang
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Re: The 3MB SRAM may be an image data buffer for GPUs
jamescpwang   10/2/2013 10:45:31 PM
Apple and tsmc rescue Apple iPhone 5S fingerprint identification chip.

The article was published in DigiTimes on August 12, 2013 in Chinese and the partial abstract is translated in English and listed below for your reference:

1)      Fingerprint ID chip production was not ready until July, 2013 by assembly issues in Xintec. The original mass production schedule of the ID chip was in May, 2013.

2)      Apple sent technical people to Taiwan and work with tsmc engineers to solve assembly and test issues in Xintec (wholly own OSAT by tsmc).

3)      Apple iPhone 5S fingerprint ID chip gets 30,000 8" wafer per month capacity from tsmc.

4)      The schedule delay may be related to a) the incompatibility between IOS7 software and ID chip hardware; b) ID chip is interfered by Sapphire blue paint and c) the new assembly methodology that results in very low yield.

5)      Both Apple and tsmc have confidence that the low yield problem will be solved and the mass production will be started by the end of August.

This may imply that the 3MB SRAM is not for storing fingerprint data and the separated fingerprint ID chip may have EEPROM on 8" wafer.

rick merritt
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Re: The 3MB SRAM may be an image data buffer for GPUs
rick merritt   10/1/2013 3:44:20 PM
One engineer with a background at mobile SpoC companies told me today its closer to a 4 Mbyte block than 3MB. He also said he believes its a L3 cache.

wave.forest
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The 3MB SRAM may be an image data buffer for GPUs
wave.forest   10/1/2013 7:57:02 AM
It may not be the GPU cache since to support cache mechanism, a cache controller is needed. This big SRAM may be an image buffer, say, to be used as ping-pong buffer, to process HD videos.

In addition, I agree it doesn't look like an L3 - not only too far away from CPU, but also no controller connected.

rick merritt
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Re: Fingerprint data storage
rick merritt   9/30/2013 8:13:47 PM
Agreed, this ~3 MByte block is probably a GPU cache

Frank Eory
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Re: Fingerprint data storage
Frank Eory   9/30/2013 4:01:12 PM
Bastian, that -- GPU cache -- is the most logical argument yet.

Bastian.Schick
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Re: Large on-chip RAM
Bastian.Schick   9/30/2013 3:53:39 PM
They do not store the fingerprint itself. Rather they store a hash value which is smaller than the actual scan data.

Bastian.Schick
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Re: Fingerprint data storage
Bastian.Schick   9/30/2013 3:50:44 PM
I have to say, that I doubt it is 3rd level cache. For one, it is to far away from the 2nd level cache. Second (correct me if I am wrong), I never saw an ARM architecture with 3rd level cache.

Also, I doubt it is GPU framebuffer, as it is far to small.But I think it is a GPU cache. It is directly between the GPU-SDRAM interface and the GPU..

rick merritt
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Re: Fingerprint data storage
rick merritt   9/30/2013 12:14:23 AM
I'm guessing the 3MByte is L3 cache or perhaps a private frame buffer memory for the quad core GPU.

wilber_xbox
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Re: Fingerprint data storage
wilber_xbox   9/29/2013 1:00:15 PM
Apple patented the fingerdata verification techinique for mobiles in very recently infact in 2012 they filed for the patent. I do not know where they store this information but 3MB looks rather too much for just few fingerprint.

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