User’s Manual
105
7.13 Input Capture
The two-channel Input Capture can be used to time input signals from various port pins.
Each Input Capture channel consists of a sixteen-bit counter that is clocked by the output
of Timer A8, and can be connected to one or two out of sixteen parallel port pins. The
Input Capture channel captures the state of its counter upon either of two programmed
conditions and can then generate an interrupt. The programmed conditions can also be
used to start and stop the counter.
Because the Input Capture channels synchronize their inputs to the peripheral clock (fur-
ther divided by Timer A8), there is some delay between the input transition and when an
interrupt is requested, as shown below. The status bits in the ICSxR are set coincident with
the interrupt request and are reset when read from the ICSxR.
Each Input Capture channel has two inputs, called the Start condition and the Stop condi-
tion. Each of these two inputs can be programmed to come from one of four bits (bits 1, 3,
5 or 7) in Parallel Port C, D, F or G. The two inputs can come from the same or different
pins, and are edge-sensitive. Each input can be disabled, rising-edge-sensitive, falling-
edge-sensitive or responsive to either edge polarity. Either or both inputs can generate an
Input Capture interrupt, and either or both inputs can cause the current count to be latched.
Register Name
Mnemonic
I/O Address
R/W
Reset
Input Capture Ctrl/Status Register
ICCSR
0x56
R/W
00000000
Input Capture Control Register
ICCR
0x57
W
xxxxxx00
Input Capture Trigger 1 Register
ICT1R
0x58
W
00000000
Input Capture Source 1 Register
ICS1R
0x59
W
xxxxxxxx
Input Capture LSB 1 Register
ICL1R
0x5A
R
xxxxxxxx
Input Capture MSB 1 Register
ICM1R
0x5B
R
xxxxxxxx
Input Capture Trigger 2 Register
ICT2R
0x5C
W
00000000
Input Capture Source 2 Register
ICS2R
0x5D
W
xxxxxxxx
Input Capture LSB 2 Register
ICL2R
0x5E
R
xxxxxxxx
Input Capture MSB 2 Register
ICM2R
0x5F
R
xxxxxxxx
CPT input
Interrupt
Peri Clock
Timer A8
Содержание Rabbit 2000
Страница 2: ...Rabbit 3000 Microprocessor User s Manual 019 0108 040731 O ...
Страница 9: ...Rabbit 3000 Microprocessor ...
Страница 29: ...20 Rabbit 3000 Microprocessor ...
Страница 64: ...User s Manual 55 5 PIN ASSIGNMENTS AND FUNCTIONS ...
Страница 79: ...70 Rabbit 3000 Microprocessor ...
Страница 80: ...User s Manual 71 6 RABBIT INTERNAL I O REGISTERS ...
Страница 123: ...114 Rabbit 3000 Microprocessor ...
Страница 137: ...128 Rabbit 3000 Microprocessor ...
Страница 157: ...148 Rabbit 3000 Microprocessor ...
Страница 207: ...198 Rabbit 3000 Microprocessor ...
Страница 249: ...240 Rabbit 3000 Microprocessor ...
Страница 255: ...246 Rabbit 3000 Microprocessor ...
Страница 277: ...268 Rabbit 3000 Microprocessor ...
Страница 343: ...334 Rabbit 3000 Microprocessor ...
Страница 345: ......