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CHAPTER 17 8/10-BIT A/D CONVERTER
17.5.1 Example of μDMAC Start in Single Mode
An example of μDMAC start in the single mode is described below.
Example of μDMAC start in single mode
■
An example of start operation is based on the conditions described below:
•
Conversion finishes after conversion up to analog input (AN1 to AN3)
•
Conversion data is transferred to addresses 200
•
Start by software
•
The highest interrupt level is used
Setting item
μDMAC setting
A/D converter setting
μDMAC end
sequence
ICR14: Interrupt control register
BAPL: Buffer address pointer lower
BAPM: Buffer address pointer middle
BAPH: Buffer address pointer higher
ISCS: Status register
IOA:
Address register
DCT:
Data counter
370
Sample program
MOV ICR14,#00H
MOV BAPL,#00H
MOV BAPM,#02H
MOV BAPH,#00H
MOV DMACS,#18H
MOV IOA,#48H
MOV DCT,#03H
MOVW DERL,#8000H
MOV ADCS1,#0BH
MOV ADCS2,#A2H
WBTC io ADCS2:7
MOV ADCS2,#000H
MOVW DSRL,#0000H
RETI
to 206
H
H
Operation
Sets highest interrupt level and enables interrupts
Address to transfer conversion data
Set DMA control status register (Transfers word data and
increments the destination address after transfer)
Stores A/D conversion results in registers
Performs three transfers, matching the number of
conversions
Setting for the μDMAC enable register (EN15)
Single mode, start channel AN1, end channel AN3
Software start, A/D conversion start
Determines end of A/D conversion
Resource interrupt clear
μDMAC status register clear
Reset from interrupt
sequentially
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