HCTL-1101 Datasheet, PDF(38/40 Page) AVAGO TECHNOLOGIES LIMITED – General Purpose Control ICs Position and Velocity Control Low Power CMOS

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HCTL-1101 Datasheet, PDF (38/40 Pages) AVAGO TECHNOLOGIES LIMITED – General Purpose Control ICs Position and Velocity Control Low Power CMOS

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OE low enables the internal outputs latch onto the exter-

nal bus. The OE signal and the internal output latch allow

the I/O port to be flexible and avoid bus conflicts during

read operations.

It is important that the host microprocessor does not

attempt to perform too many I/O operations in a single

sample time of the HCTL-1101. Each I/O operation inter-

rupts the execution of the HCTL-1101âs internal code for

1 clock cycle.

Although extra clock cycles have been allotted in each

sample time for I/O operations, the number of extra cycles

is reduced as the value programmed into the Sample Tim-

er register (R0FH) is reduced.

Table 5 shows the maximum number of I/O operations al-

lowed under the given conditions.

The number of external clock cycles available for I/O oper-

ations in any of the four control modes can be increased by

increasing the value in the Sample Timer register (R0FH).

For every unit increase in the Sample Timer register (R0FH)

Table 5. Maximum Number of I/O Allowed

above the minimums shown in Table 5 the user may per-

form 16 additional I/O operations per sample time.

Interfacing the HCTL-1101 to Amplifiers and Motors

The Motor Command port is the ideal interface to an 8-

bit DAC, configured for bipolar output. The data written to

the 8-bit Motor Command port by the control algorithms

is the internally computed 2âs-complement motor com-

mand with an 80H offset added. This allows direct inter-

facing to a DAC. Figure 16 shows a typical DAC interface

to the HCTL-1101. An inexpensive DAC, such as MC1408

or equivalent, has its digital inputs directly connected to

the Motor Command port. The DAC pro-duces an output

current which is converted to a voltage by an operational

amplifier. RO and RG control the analog offset and gain.

The circuit is easily adjusted for +5 V to â5 V operations by

first writing 80H to R08H and adjusting RO for 0 V output.

Then FFH is written to R08H and R is Adjusted until the

output is 5 V. Note that 00H in R08H corresponds to â5 V

out. Figure 17 shows an example of how to interface the

HCTL-1101 to an H-bridge amplifier. An H-bridge ampli-

fier allows bipolar motor operation with a unipolar power

supply.

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