[flashrom] [coreboot] Tester devices [was: QA contribution]

Juhana Helovuo juhe at iki.fi
Thu Feb 17 21:13:59 CET 2011

Carl-Daniel Hailfinger wrote:

> If you tell me about the design constraints of your device, I can
> probably come up with a flashrom driver which can reflash an 1 MByte ROM
> in ~5 minutes or so. That will require some cooperation from your
> device, but should be doable with ~270 bytes of RAM. Even with ~140
> bytes of RAM we should be able to get some decent performance. As long
> as we can optimize the protocol, it should be possible to get acceptable
> performance even with only 50 bytes of RAM, but generally more RAM will
> give you better performance.

The tester device is basically an Atmel AT90USB162, which has USB and 
SPI ports. Data sheet and a detailed manual are available on Atmel web 
pages. The USB is connected to the Linux host. SPI and some I/O pins are 
used to control a multiplexer and an SPI flash chip.

The microcontroller can be programmed in C with gcc, and I am using the 
open-source LUFA library for USB drivers on the device side.

The microcontroller has 16 Kbytes Flash ROM, 512 bytes SRAM, and a 
separate 176 byte buffer RAM in the USB controller. The CPU runs at 16 
MHz. I have so far used the SPI bus at 1 MHz.

The USB controller supports up to 5 endpoints, including default control 
endpoint. Maximum packet size is 64 bytes. Two of the endpoints can be 
double buffered in hardware.

Is this enough details, or do you need something else?

Best regards,
Juhana Helovuo

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