Author: Kaslai
Posted: 01 Dec 2012 09:01:07 pm (GMT -5)
Well, I haven't studied much about TI hardware, but I know that most DRAM has to be refreshed every 64 milliseconds in order to guarantee it stays intact. Even when the AAA batteries are pulled out, the little button cell keeps the refresh cycle going on a TI calc. Now, when you yank the AAAs out when the calculator is running, the hardware only provides a few milliseconds of processing time. During TI-OS routines, it can usually use this time to validate RAM. During ASM code execution though, it can't guarantee that the RAM is still safe. This actually benefits the user though. If an ASM program starts an endless loop, you'd want a RAM reset. The TI-OS has decades of testing behind it though, and is guaranteed to get stuck in a never ending loop.
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Posted: 01 Dec 2012 09:01:07 pm (GMT -5)
| Tom wrote: |
| The ram will be preserved for about 20-40 seconds even after the power is completely cut since the ram is actually a bunch of capacitors. |
Well, I haven't studied much about TI hardware, but I know that most DRAM has to be refreshed every 64 milliseconds in order to guarantee it stays intact. Even when the AAA batteries are pulled out, the little button cell keeps the refresh cycle going on a TI calc. Now, when you yank the AAAs out when the calculator is running, the hardware only provides a few milliseconds of processing time. During TI-OS routines, it can usually use this time to validate RAM. During ASM code execution though, it can't guarantee that the RAM is still safe. This actually benefits the user though. If an ASM program starts an endless loop, you'd want a RAM reset. The TI-OS has decades of testing behind it though, and is guaranteed to get stuck in a never ending loop.
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