topic Re: UM10601 problems in LPC81x user manual in LPC Microcontrollers

UM10601 problems in LPC81x user manual

lpcware — Wed, 15 Jun 2016 19:59:50 GMT

Content originally posted in LPCWare by Rob65 on Fri Nov 07 03:19:01 MST 2014
I am reading rev 1.6 of UM10601 recently downloaded from nxp.com and found some errors:

In section 10.6 (page 136) the definition of REGMODEn bits is wrong.Here it is described that a 1 means "match and reload" and 0 is "capture and capture control"

But table 130 on page 146 states the opposite (0 = match, 1 = capture).
Looking at the example it seems that the table is correct.

This makes it very hard to use the SCT. The part is too complex to just use out-of-the-box (yes - because of all the nice features it has).

Another problem arises when we tried to use the Deep power-down mode.

The user manual does not explain that the DPDFLAG in the LPC_PMU->PCON registers must be cleared before entering deep power-down mode.
The manual (see page 66) gives 6 steps with step 2 "Ensure that bit 3 in the PCON register is cleared".
Table 56 (page 59) is referenced and here it is stated that if bit 3 is set, the part deep power-down mode is blocked.

But when the DPDFLAG is not cleared before writing 0x3 into the PCON register to enter deep power-down mode, entering deep power-down mode seems to be locked also.
At least, that is what we noticed while forgetting to clear the DPDFLAG.

Since deep sleep and power down modes are very hard to debug, this made me banging my head against the wall for a few hours before discovering what was missing ...

Re: UM10601 problems in LPC81x user manual

lpcware — Wed, 15 Jun 2016 19:59:51 GMT

Content originally posted in LPCWare by nerd herd on Fri Nov 07 09:42:31 MST 2014
Hello Rob65,

The contradiction in regards to the REGMODEn bits will be reported. Thank you for finding that issue!

As for the Deep Power-down issue...are you using the LPC 800 low power modes application note or are you writing your own software to enter Deep Power-down? Link to the AN is here:

http://www.lpcware.com/content/nxpfile/lpc800-low-power-modes-and-wake-times

Re: UM10601 problems in LPC81x user manual

lpcware — Wed, 15 Jun 2016 19:59:51 GMT

Content originally posted in LPCWare by IanB on Sat Nov 08 14:43:49 MST 2014
The manual isn't too clear on the SCT interrupt either.

Am I correct in thinking that the interrupt handler should clear the EVFLAG register by writing 0x1F to it? Otherwise the interrupt repeats indefinitely.

In the Red State software, how do I set the clock source and the prescalers?

Re: UM10601 problems in LPC81x user manual

lpcware — Wed, 15 Jun 2016 19:59:52 GMT

Content originally posted in LPCWare by Rob65 on Sun Nov 09 00:43:31 MST 2014

Quote: nerd herd
are you using the LPC 800 low power modes application note or are you writing your own software to enter Deep Power-down?

a bit of both. I already have a lot of experience with different NXP processors (ever heard of PNX5210 or PNX4008 :bigsmile: ).
The problem is that we do not use either Keil or LPCXpresso but CrossWorks for ARM and the coding rules are a bit different, so with my knowledge about clock generation and power management I mostly start with the user manual - being the main reference, this one should contain all information needed.

The application note contains excerpts from the user manual with nice explanations and it is the code with the Application note that made me find the issue.

Regards,

Rob