Remote-processing RPC-2350 Bedienungsanleitung PDF herunterladen (Seite 58)

CHAPTER 14 MULTI-MODE COUNTER

14-3

Figure 14-1 Counter and jumper location

CHAPTER SYNOPSIS

 Brief description of the counter

 High voltage input and level sensing adjustment

 Use in program

 Measuring pulse w idth

 Measure frequency

DESCRIPTION

MUL TI-MODE COUNTER CH APTE R 14

The RPC-2350 has a programmable high speed counter

or quadratur e encoder . The 24-bit counters are capable

of up/down, binar y, divide-by-n, and qu adrature inpu ts.

Count frequency is DC to 20 MHZ. The type of counter

is an LSI C omputer Systems L S7166. Its data sheet is in

Appendix A and on disk as LS7166.PDF

COUNT(8) is used to read the counter. The OUT

command is used to write and program the chip.

An interrupt, using ON ITR 1, may be detected on a

carry or borrow.

A high voltage input, such as a signal from a proxim ity

sensor, may be connec ted to one of the inputs.

Signals connect via J10. All input lines are pulled high

through 10K input resistors. A quadrature encoder may

be connected directly to J10.

A count is incremented when the signal at the ‘A’ input

goes from low to high.

COUNTER INPUTS AND OUTPUTS

The counter chip has four inputs and two outputs.

Reference is made to the LS7166 counter registers.

These registers are in Appendix A at the end of this

manual.

Two of the inputs, designated as A and B, are counter

inputs. The ICR (input control register) controls the

function of these inputs. Encoders, switches, and other

such devices are con nected to these inputs. These inputs

are very high speed. If you are going to use a

mechanical switch, it is best to debounce it first or use

the high voltage input described below.

The ‘A’ input (J10-9 or J10-10 through buffer) operates

as up and dow n count input and a quadrature input.

The ‘B’ input (J10-8) can a ct as a down count input,

direction control for input A, or a quadrature input.

Another input is LCTR (J10-6). It can load the counter

or output latch. The ICR register controls the function

of this line. If using it to control the output latch, you

must read each register individually and not transfer the

counter to the output latch as is done by COUN T(8).

See CNTR5.BAS.

The ABGT input (J10-4) enables/disables A/B inputs or

resets the counter. The IC R regsiter controls the

function of this line. Nor mally, it does not have to be

accessed.

The two outputs, CY and BW are counter carry and

borrow signals. They are use to generate an interrupt

(INT1) when the counter goes either through 0 or a

preset. These outputs are controlled by the OCCR

Interrupt selection

Jumper W7 can be used to interrupt the CPU on a

counter carry, borrow, or external interrupt. Jumper

W7[1-2] to interrupt on a carry (counter overflows). Set

jumper W7[2-3] to interrupt on a borrow (counter

underflow). Leave W7 open if using an external

interrupt. INT1 goes to J10-2 for external interrupts.

See Figure 14-2 for W7 jumper pin out.

1 2 ... 53 54 55 56 57 58 59 60 61 62 63 ... 82 83

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