Struct lpc845_pac::capt::ctrl::R [−][src]
pub struct R(_);
Expand description
Register CTRL
reader
Implementations
Bits 0:1 - Mode of operation. May only change from 0 to another value. So, if 2 or 3, must be changed to 0 1st. Any attempt to go from non-0 to non-0 will result in 0 anyway.
Bits 2:3 - Selects type of Touch arrangement to use and so how to handle XPINSEL bits
Bit 5 - If 0, the block will continue its X based measurements, even if the TOUCH register has not been read (and so could OVERRUN). If 1, it will wait until read when a touch (TOUCH’s ISTOUCH bit is set) before starting the next. This should not normally be needed.
Bits 6:7 - If not 0, will use the DMA to read out touch events from TOUCH register. The values are shown below. This may be changed while active.
Bits 8:11 - Functional clock divider, or 0 if no divide. The term “clocks” in this spec then refer to divided clocks. For a 12MHz input (e.g. FRO 12MHz), this would normally be set to generate a 4MHz output (so, 2). For a 1MHz input, it should be 0. Note for internal use: this does not produce a 50/50 duty cycle when non even divide.
Bits 12:13 - Controls how X pins selected in XPINSEL are used when not active in the current polling round.
Bit 15 - If 1, do not attempt to write to this register again. This means the last change has not been propagated. This can only happen after changing POLLMODE and DMA. Worse case time would be based on divided FCLK.
Bits 16:31 - Selects which of the X pins are to be used within the allowed pins - see XMAX in STATUS. The X pins are mapped via the IOCON (as are the YH and YL pins) to physical pads. So, this only selects which are to be used as the X half of the touch element. Note: when polling, these are “walked” (active) one at a time. When using POLLNOW, the 1 or more selected are used at the same time. Likewise, when in low-power mode, they are used at the same time (or small groups). X pads not selected by XPINSEL are kept at High-Z if they are connected to a pad. This allows using controlled sets for touch detection based on context.