Datasheet

© 2007-2012 Microchip Technology Inc. DS70291G-page 229
dsPIC33FJ32MC302/304, dsPIC33FJ64MCX02/X04 AND dsPIC33FJ128MCX02/X04
17.2 QEI Control Registers
REGISTER 17-1: QEIxCON: QEIx CONTROL REGISTER (x = 1 or 2)
R/W-0 U-0 R/W-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0
CNTERR
(1)
— QEISIDL INDEX UPDN
(2)
QEIM<2:0>
bit 15 bit 8
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
SWPAB PCDOUT TQGATE TQCKPS<1:0> POSRES TQCS UPDN_SRC
bit 7 bit 0
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
bit 15 CNTERR: Count Error Status Flag bit
(1)
1 = Position count error has occurred
0 = No position count error has occurred
bit 14 Unimplemented: Read as ‘0’
bit 13 QEISIDL: Stop in Idle Mode bit
1 = Discontinue module operation when device enters Idle mode
0 = Continue module operation in Idle mode
bit 12 INDEX: Index Pin State Status bit (read-only)
1 = Index pin is High
0 = Index pin is Low
bit 11 UPDN: Position Counter Direction Status bit
(2)
1 = Position Counter Direction is positive (+)
0 = Position Counter Direction is negative (-)
bit 10-8 QEIM<2:0>: Quadrature Encoder Interface Mode Select bits
111 = Quadrature Encoder Interface enabled (x4 mode) with position counter reset by match
(MAXxCNT)
110 = Quadrature Encoder Interface enabled (x4 mode) with Index Pulse reset of position counter
101 = Quadrature Encoder Interface enabled (x2 mode) with position counter reset by match
(MAXxCNT)
100 = Quadrature Encoder Interface enabled (x2 mode) with Index Pulse reset of position counter
011 = Unused (Module disabled)
010 = Unused (Module disabled)
001 = Starts 16-bit Timer
000 = Quadrature Encoder Interface/Timer off
bit 7 SWPAB: Phase A and Phase B Input Swap Select bit
1 = Phase A and Phase B inputs swapped
0 = Phase A and Phase B inputs not swapped
bit 6 PCDOUT: Position Counter Direction State Output Enable bit
1 = Position Counter Direction Status Output Enable (QEI logic controls state of I/O pin)
0 = Position Counter Direction Status Output Disabled (Normal I/O pin operation)
Note 1: This bit only applies when QEIM<2:0> = ‘110’ or ‘100’.
2: Read-only bit when QEIM<2:0> = ‘1XX’. Read/write bit when QEIM<2:0> = ‘001’.
3: Prescaler utilized for 16-bit Timer mode only.
4: This bit applies only when QEIM<2:0> = 100 or 110.
5: When configured for QEI mode, this control bit is a ‘don’t care’.