ISD94100 Series Technical Reference Manual
Sep 9, 2019
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PERIOD DATA1 denotes the first updated PERIOD data by user and so on, CMP also follows this
rule. The following steps are the sequence of Figure 6.7-18.
1.
User writes CMP DATA1 to CMP at point 1.
2.
Period loading CMP DATA1 to CMPBUF at the end of PWM period at point 2.
3.
User writes PERIOD DATA1 to PERIOD at point 3.
4.
Period loading PERIOD DATA1 to PBUF at the end of PWM period at point 4.
5.
User writes PERIOD DATA2 to PERIOD at point 5.
6.
Period loading PERIOD DATA2 to PBUF at the end of PWM period at point 6.
CNT
PERIOD DATA0
PERIOD DATA1
CMPDAT DATA1
PERIOD DATA0
PERIOD DATA1
CMPDAT DATA1
PERIOD DATA2
PERIOD DATA2
point 1
point 2
point 3 point 4
point 5
point 6
CMPDAT DATA0
CMPU
CMPDAT DATA1
PERIOD DATA0
PERIOD DATA1
PERIOD DATA2
CMPDAT
PERIOD
PBUF
CMPBUF
0x10000
Write
Load
Note:
Figure 6.7-18 Period Loading Mode with Up Count Type
6.7.6.9
Immediately Loading Mode
When the IMMLDEN (TIMERx_PWMCTL[9]) bit set to 1, PWM operates at immediately loading
mode. In immediately loading mode, when user update PERIOD (TIMERx_PWMPERIOD[15:0]) or
CMP (TIMERx_PWMCMPDAT[15:0]), PERIOD or CMP will be load to active PBUF
(TIMERx_PWMPBUF[15:0]) or CMPBUF (TIMERx_PWMCMPBUF[15:0]) after current counter
count is completed. If the update PERIOD value is less than current counter value, counter will
count wraparound. The following steps are the sequence of Figure 6.7-19.
1.
User writes CMP DATA1 at point 1 and hardware will load CMP DATA1 to CMPBUF after
current counter count is completed.
2.
User writes PERIOD DATA1 at point 2 and PERIOD DATA1 is greater than current counter
value, PWM counter will continuously count until equal to PERIOD DATA1 to complete one
PWM period.
3.
User writes PERIOD DATA2 at point 3 and PERIOD DATA2 is less than the current counter
value, PWM counter will continuously count to maximum counter value 0x1FFFF and
wraparound from 0x10000 to PERIOD DATA2 to complete one PWM period.