...
That seems a little pointless. I have (a long time ago) uploaded a file to the P2K group including a description of the pin functions called "SIMM pinouts.txt". Its in one of the sub folders there.
From a reading point of view, a FLASH device looks like a linear address map (although through special commands there is often other information that you can read in a non-linear fashion). From a writing point of view, it is written by blocks/pages which tend to be 64K words in size (but can vary from device to device) although some devices have a bunch of smaller pages at one end of the address range. The reason for the paging is not so much writing but for erasing. A single command can either erase a page, erase a lock or erase the entire device depending on the way the device is laid out.Erasing sets all bytes to 0xFF, and writing changes bits from '1' to '0'. You can write
memory locations multiple times but the only changes that will be effected are bit transitions from '1' to '0'. That is, if you write a byte from 0xFF to 0xF0, the result will be 0xF0, but if you then write 0xAA to that 0xF0 byte, the result will be 0xA0.�
From: "Andre Lewis bassmeister3000@... [xl7]"
To: "xl7@yahoogroups.com"
Sent: Thursday, 17 July 2014 5:50 AM
Subject: Re: [xl7] Any interest remaining in a self-programming FLASH SIMM?
To: "xl7@yahoogroups.com"
Sent: Thursday, 17 July 2014 5:50 AM
Subject: Re: [xl7] Any interest remaining in a self-programming FLASH SIMM?
�
Exactly. �One ARM chip to deal with the transforms for the data, and loading samples/patches/etc dynamically from SD. �Since there are plenty of ARM libs for dealing with SD, it becomes a matter of getting the right signal to the right pin on the device at the right time. �
The flash on the cards seems to use
a 16bit hardware bus, using paging to
get to different parts of the flash memory. �Still a little confusing, so reading through this again. �But it definitely seems there are a lot more pins on the expansion card than there needs to be. �It makes me think that either they break out the flash chips to their own set of pins, or there are a lot of unconnected or ground/vcc pins. �The flash also apparently has it's own processor and command set for reading/writing the chip. �Since it looks like the flash can take either direct pin writes or using the command set, we would need to figure out which one the the expansion is wired for. �
Anyone have an expansion card out that they could take a picture of with a light behind it? �Front and back. Preferably high resolution. �Might not see anything with a four layer card, but might show vias and the traces.
Andre
On Wednesday, July 16, 2014 12:04 PM, "janoch23@... [xl7]" wrote:
�
The microcontroller needs some storage from which to load sample data into the SRAMs emulating Flash chips at bootup. That storage could be an SD card. In that case all you need for a panel mount SD slot would be an SD extension cable.
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