NPM Motionnet G9001A, Руководство пользователя

Страница: 58 / 125

DA70131-1/3E
II-8
4-4. Functions of terminals
4-4-1. CLK
This is an input terminal of the reference clock. By setting of the CKSL terminal, either of the following clock rate
signals can be connected.
CKSL = L: 40 MHz
CKSL = H: 80 MHz
By selecting either of these clock rates, the serial communication transfer rate does not change. This clock rate
selection affects communication precision.
For a small-scale serial communication and transfer rate below 10 Mbps, use of the center device with 40 MHz
does not give any restriction.
With 20 Mbps transfer speed; however, a longer communication line or a large number of connected local devices
may deteriorate communication precision due to collapse of signals on the circuit. This deterioration of
communication quality can be corrected inside the LSI, if the deterioration level is not much. In order to improve
correction precision, evenness of the clock duty is required. In other words, if the duty is ideal (50:50), the capacity
to correct collapse of the signals in the communication lines can be improved. On the contrary, if the duty is not
ideal, the center device cannot cope with collapses of the communication line.
As a result, if the duty is close to ideal, the center device can be used with 40 MHz. When connecting more than
one oscillators, the duty will not be ideal. In this case, select 80 MHz. The center device divides the frequency
inside and creates 40 MHz frequency.
If you do not want to 80 MHz frequency, you may prepare a separate 40 MHz oscillator for this LSI.
4-4-2.
____
RST
This is an input terminal for a reset signal.
By input L level signal, the center device is reset. As the center device synchronizes with a clock, arrange a circuit
so that it does not disconnect the clock while resetting. Reset signal length longer than 10 clock cycles is required.
4-4-3. CKSL
Use to select clock rate.
L: Connect 40 MHz clock frequency to the CLK terminal.
H: Connect 80 MHz clock frequency to the CLK terminal.
Select this when the duty of the 40 MHz clock collapses too much.
4-4-4.
____
DN0 to
____
DN5
Input terminals for setting device address.
Since these terminals use negative logic, setting all the terminals to zero calls up device address "3Fh."
There are two methods for entering a device address. Select the input method using the DNSM terminal.
4-4-5. DNSM
Select the input method for loading the device address.
1) When the DNSM = H
Specify an address from 00h to 3Fh using the
____
DN0 to
____
DN5 terminals.
2) When the DNSM = L
Input a
_____
DNSO signal that is output by some other chip on the
____
DN0 terminal on this device. When using this
input method, this chip has an address equal to the other chip's address plus one.
When using this method, connect terminals
____
DN1 to
____
DN5 to GND.
When two sequential sets of serial data match, the data is taken to be a device address.