Microchip Technology dsPIC30F - Page 383

© 2004 Microchip Technology Inc. DS70064C-page 17-7
Section 17. 10-bit A/D Converter
10-bit A/D
Converter
17
Register 17-2: ADCON2: A/D Control Register 2
Upper Byte:
R/W-0 R/W-0 R/W-0 U-0 U-0 R/W-0 R/W-0 R/W-0
VCFG<2:0>
reserved — CSCNA CHPS<1:0>
bit 15 bit 8
Lower Byte:
R-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
BUFS
— SMPI<3:0> BUFM ALTS
bit 7 bit 0
bit 15-13 VCFG<2:0>: Voltage Reference Configuration bits
bit 12 Reserved: User should write ‘0’ to this location
bit 11 Unimplemented: Read as ‘0’
bit 10 CSCNA: Scan Input Selections for CH0+ S/H Input for MUX A Input Multiplexer Setting bit
1 = Scan inputs
0 = Do not scan inputs
bit 9-8 CHPS<1:0>: Selects Channels Utilized bits
1x = Converts CH0, CH1, CH2 and CH3
01 = Converts CH0 and CH1
00 = Converts CH0
When SIMSAM bit (ADCON1<3>) = 0 multiple channels sampled simultaneously.
When SMSAM bit (ADCON1<3>) = 1 multiple channels sampled as in CHPS<1:0>.
bit 7 BUFS: Buffer Fill Status bit
Only valid when BUFM = 1 (ADRES split into 2 x 8-word buffers).
1 = A/D is currently filling buffer 0x8-0xF, user should access data in 0x0-0x7
0 = A/D is currently filling buffer 0x0-0x7, user should access data in 0x8-0xF
bit 6 Unimplemented: Read as ‘0’
bit 5-2 SMPI<3:0>: Sample/Convert Sequences Per Interrupt Selection bits
1111 = Interrupts at the completion of conversion for each 16th sample/convert sequence
1110 = Interrupts at the completion of conversion for each 15th sample/convert sequence
.....
0001 = Interrupts at the completion of conversion for each 2nd sample/convert sequence
0000 = Interrupts at the completion of conversion for each sample/convert sequence
bit 1 BUFM: Buffer Mode Select bit
1 = Buffer configured as two 8-word buffers ADCBUF(15...8), ADCBUF(7...0)
0 = Buffer configured as one 16-word buffer ADCBUF(15...0.)
bit 0 ALTS: Alternate Input Sample Mode Select bit
1 = Uses MUX A input multiplexer settings for first sample, then alternate between MUX B and MUX A input
multiplexer settings for all subsequent samples
0 = Always use MUX A input multiplexer settings
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
A/D VREFH A/D VREFL
000
AVDD AVSS
001
External VREF+ pin AVSS
010
AVDD External VREF- pin
011
External VREF+ pin External VREF- pin
1XX
AVDD AVSS