LPC1769 MCPWM Problem

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LPC1769 MCPWM Problem

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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by Ulisses on Mon Dec 19 11:49:15 MST 2011
There is a problem in LPC1769 MCPWM module.

The System Frequency is 120 MHz and PCCLK = CCLK for the MCPWM.
It was setup for CENTER ALIGNED and ACMODE.

For switching frequency higher than 5 kHz and modulation index higher than 0.8 or lower than 0.2, it seems to stop working every 4-5 ms for about 2ms.

Example:
SystemFrequency = 120000000
PCCLK_MC = 1
LPC_MCPWM->LIM(0,1,2) = 12000
LPC_MCPWM->MAT(0,1,2) = 11500 or 500
LPC_MCPWM->CENTER(0,1,2) = 1
LPC_MCPWM->POLA(0,1,2) = 0
LPC_MCPWM->DTE(0,1,2) = 0
LPC_MCPWM->DISUP(0,1,2) = 0
INVBDC = 0
ACMODE = 1
DCMODE = 0
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199 Views
lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by Ulisses on Tue Dec 20 12:10:07 MST 2011
I got some waveforms as an example.

Duty cycle = 50% -> OK
Duty cycle = 95% -> The MCPWM stops every 5ms.
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