User Manual

Apollo3 Blue Datasheet

DS-A3-0p9p1 Page 571 of 909 2019 Ambiq Micro, Inc.

13.18.2Counting Buck Converter Edges

Apollo3 includes three separate buck converters which provide power for the Processor power domain

(BUCKA), the Memory power domain (BUCKB) and the BLE interface module (BUCKBLE). Each CTIMER

may be connected to a pulse stream from any of the three analog Buck Converters. One pulse is

generated each time the Buck Converter inserts charge into the capacitor, and therefore the number of

pulses is a good indication of the amount of energy used by the corresponding power domain in a

particular time period.

A possible option to determine energy consumption is as follows. Two counters could be configured with

FN = 6 so that they count continuously. One is supplied a Buck Converter pulse stream as its clock, and

the other is supplied with a divided version of the LFRC clock to avoid creating extra power consumption

due to the power measurement. Once configured such, the two counters should be enabled

simultaneously, and after some period of system operation they should be disabled and read. The LFRC

count value would now define how much real time has elapsed, and the Buck Converter count value would

define how much energy was consumed in that time.

13.19Interconnecting CTIMERs

The OUT or OUT2 output of one CTIMER may be used as either the Trigger or the clock of another

CTIMER. Figure 83 shows the interconnection structure for two example CTIMERs, where p and q are A

or B and x and y are 0 through 7. The selection of the actual clock or trigger interconnection is made within

each CTIMER. The interconnection Matrix is not complete, as each CTIMER can select from only 15

triggers and 12 external clocks.

Figure 83. CTIMER Interconnection

CTIMERpx

CTIMERqy

ctimerpx_out

ctimerpx_out2

ctimerpx_extclk

ctimerpx_trig

ctimerqy_out

ctimerqy_out2

ctimerqy_extclk

ctimerqy_trig

Interconnection Matrix (no logic)

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