Lpc2000

I did a few more tests to see if I could get any more speed, but I
wasnt able.  I wish the PLL had a few more steps, cause my only next
step is 88.6 Mhz, maybe I should of used a 10 Mhz xtal in the design.
 Here is an updated table:

+---+---+----------+-------+---------+-------+
|PLL|MAM| SYS CLCK | FLASH | CURRENT | SPEED |
+---+---+----------+-------+---------+-------+
| 4 | 3 | 59.0 Mhz | 51 ns | 56.5 mA | 100 % |
| 4 | 2 | 59.0 Mhz | 34 ns | 59.0 mA | 116 % |
| 5 | 4 | 73.7 Mhz | 54 ns | 65.0 mA | 108 % |
| 5 | 3 | 73.7 Mhz | 41 ns | 67.3 mA | 123 % |
| 6 | 3 | 88.6 Mhz | 34 ns | 79.9 mA | 146 %*| 
| 6 | 4 | 88.6 Mhz | 45 ns | 00.0 mA | 000 %&|
| 6 | 5 | 88.6 Mhz | 56 ns | 71.9 mA | 108 %@|
+---+---+----------+-------+---------+-------+

* Unstable - Freeze in under 60 seconds.
& Could not start up.
@ Other issue (BAD UART TX / duplicate characters)


Anyways seems like 73.7 Mhz with 41ns access time is nice and stable.
 Would be interesting to try 80.0 Mhz with 37.5ns access time.  Maybe
tomorrow I'll swap out the xtal, and try it.

Cheers,
Mark



>
> Mark,
> 
> put your finger on top of the chip, as long as this does not feel
> uncomfortably warm there should be no damage or shortened life cycle. 
> To have a lottle headromm, you want to overclock the CPU a lot more
> than you did and try to find out when it fails. Then go backwards from
> there. 
> Tests we did showed flakiness when MAMTIM was set to 3 and running the
> core at approx. 100 MHz!
> With MAMTIM set to 4 even 100 MHz at room temp seemed stable. Te
> devices got warm but not hot. Keep in mind that external temps of 85C
> could change the picture a little bit.
> IMHO, 
> the LPC213x runs easily at 80 MHz with your calculated access time
> between 35 and 40ns seems very save.
> 
> Bob
>