lpcware

LPC1788 and FLASHCFG settings

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by wella-tabor on Thu Feb 05 04:32:42 MST 2015
Hello,

I am little bit confused about the settings for FLASHCFG. I am running lpc1788 at 120 MHz with boost = on. According to the User Manual Rev. 3.1 — 15 September 2014 there should be set a value
Quote:
0x4 - Flash accesses use 5 CPU clocks. Use for up to 100 MHz CPU clock with power boost off (see Section 3.12.6). Use this setting for operation from 100 to 120 MHz operation with power boost on

.

In the previous manual there was information about using the val 0x3 for 100 to 120 MHz operation with power boost on. The default value is also set to 0x3 ( I would say it is a safe value not counting the 0x5).

The lpcopen demo code is using 120 Mhz, boost=on and no settings for FLASHCFG,  in the source code, there is mentioned
#if defined(CHIP_LPC177X_8X) || defined(CHIP_LPC40XX)
FLASHTIM_120MHZ_CPU = 3,/*!< Flash accesses use 5 CPU clocks. Use for up to 120 MHz CPU clock with power boot on*/
#else
FLASHTIM_120MHZ_CPU = 4,/*!< Flash accesses use 5 CPU clocks. Use for up to 120 Mhz for LPC1759 and LPC1769 only.*/
#endif


What value should I set for 120 MHz with boost = on?

Best
Martin

Outcomes