Product Specs

Table Of Contents
37 SAADC Successive approximation analog-
to-digital converter
Page
362
Data RAM
Figure 101: ADC
If the RESULT.PTR is not pointing to the Data RAM region, an EasyDMA transfer may result in a HardFault
or RAM corruption. See Memory on page 23 for more information about the different memory regions.
The EasyDMA will have finished accessing the RAM when the END or STOPPED event has been
generated.
The RESULT.AMOUNT register can be read following an END event or a STOPPED event to see how many
results have been transferred to the Result buffer in RAM since the START task was triggered.
In Scan mode, the size of the Result buffer must be large enough to have room for a minimum one
result from each of the enabled channels. To secure this, RESULT.MAXCNT must be specified to
RESULT.MAXCNT >= "number of channels enabled". See Scan mode on page 360 for more information
about Scan mode.
37.7 Resistor ladder
The ADC has an internal resistor string for positive and negative input.
See Figure 102: Resistor ladder for positive input (negative input is equivalent, using RESN instead of
RESP) on page 363. The resistors are controlled in the CH[n].CONFIG.RESP and CH[n].CONFIG.RESN
registers.
Result 0
Result 1
0x20000000
0x20000002
0x20000010
Result 2
0x20000012
Result 3
0x20000020
0x20000022
Sample and convert RAM
Sample and convert RAM
Sample and convert RAM
Sample and convert RAM
1
2
3
0
0
Lifeline
ADC
END_START = 1
RESULT.PTR = 0x20000000
RESULT.MAX
CNT
START
RESULT.PTR = 0x20000010
SAMPLE
STARTED
SAMPLE
END
START
RESULT.PTR = 0x20000020
STARTED
SAMPLE
SAMPLE
END
START