Schematics of delabs

74HCU04 is a chip that was made for this purpose, HCT may not work for such a circuit. C1 and C2 can go to upto 33pF and R2 can be increased to make R2 * C2 = t. Time constant much less than the period T of the crystal T = 1/F . This is to remove higher… more »

This is the continuation of the earlier post. Part of 80C39 based Process Controller. In this schematic you can see the Watchdog and D/A Converter. 80C39 and MCS48 based Process Controller is the main circuit that has the LED 7 segment display for… more »

I had to once interface an high voltage circuit to PC, The uC had to communicate thru RS232--Comm port--Serial Port. Part of the 80C31 8051 SBC Even though i had isolation at the sensors and actuators to make doubly sure the PC also has been isolated.… more »

This is the standard configuration on how to Interface a uC like 8051 to PC RS232 with MAX232A. The UART or Serial port was not present in 8049/8749 chips which were the ancestors of 8051/8031. Pages of code were needed to make a software UART in… more »