74165 Prallel in serial out shift register

Status
Not open for further replies.

ee04jjn

New Member
hi, I am trying to convert A,B,C,D input to serial output using 74165

now I connected to ABCD and gnerated clock to input clock ABCD of 74165 but I cant use the other EFGH and I dont know what shift load and the other inputs are for but I badly want to do it quickly


+--()--+
SH - /LD | 1 16| Vcc
CLK | 2 15| CLK INH
E | 3 14| D
F | 4 13| C
G | 5 12| B
H | 6 11| A
/Qh | 7 10| SER
GND | 8 9| Qh
+------+
 
I would suggest you get a datasheet for this chip. It has timing diagrams and a shows a typical Shift, load, and inhibit sequence.
In any case, here is what I see is required on a typical parallel load:
1. Clock inhibit (pin 15) high
2. Serial input (Pin 10) low
3. Clock (pin 2) Don't care
4. Data pins a-h; parallel load data
5. Shift load (pin 1) low pulse
When the shift load is pulsed low, data on pins a-h are loaded into the registers provided inhibit is high and serial input is low. If you are NOT chaining these register chips, then suggest you permanently hold the serial input pin low to avoid problems with the parallel load sequence.

Once data is loaded and you want to shift it out serially:
1. Shift load; high
2. clock inhibit; low
3. clock; high pulses
Once the clock inhibit is lowered, the clock lead pulses are used to shift out the data bits from most significant to least significant (h to a)

Dialtone
 
I am not sure I fully understand your needs, but I am assuming you only want to process 4 bits of data thru the shift register at any one time. If that is the case, simply parallel load the data into bit positions e-h using the conditions I described above, then set the control leads for serial shift out and apply 4 clock pulses to shift out the data bits. Remember that the data bits will come out in reverse order, that is h to e.

If you are just experimenting with the chip, you can simulate all the required inputs using simple switches, and watch the output using an LED/resistor.

Dialtone
 
Status
Not open for further replies.
Cookies are required to use this site. You must accept them to continue using the site. Learn more…